Modest Maps JS Changelog.

Following the semantic versioning recommendation best we can:

   "Consider a version format of X.Y.Z (Major.Minor.Patch).
    Bug fixes not affecting the API increment the patch version,
    backwards compatible API additions/changes increment the
    minor version, and backwards incompatible API changes increment
    the major version." -- http://semver.org/

v0.21.0
- Returns `this` from `map.addCallback()`, `map.removeCallback()`,
  and `map.dispatchCallback()`

v0.20.0
- Adds `map.destroy()` method, and in that process, allows all
  handlers to be removable with a `.remove()` function.

v0.19.1
- Removes unused 'parent' argument to `com.modestmaps.RequestManager`

v0.19.0
- Adds a second parameter to `map.setExtent()` which, if true,
  allows the extent set to place the map at a non-integer zoom level.
  By default, `setEvent` will behave as before.

v0.18.5
- Address issue where display:none on parent affects size detection
  (thanks @tmcw)
- Remove arbitary default map size - parent size is used always unless
  dimensions are specified. Use setSize to override at any time.

v0.18.4
- Fix Location.interpolate between the same location
- Fix DragHandler - remove inertia code

v0.18.3
- enforce limits when zooming and panning so that map functions are correct
  when returning and before the deferred draw call using getFrame

v0.18.2
- revert to @tmcw's original getFrame (simpler version broke in Chrome)

v0.18.1
- revert Coordinate.toKey to string joining
- fix up utils.js functions so that tests run again
- modify double-tap thresholds and adjust onPinched behavior
- a few more cleanups in TouchHandler (mainly to use MM.Point functions)

v0.18.0
- many tiny formatting/syntax fixes; thx JSHint!
- MM.moveElement is used for tile positioning
- MM.moveElement detects and uses CSS transforms wherever possible
- MM.bind is used for function binding instead of awkward closures
- MM.getFrame is used to request redraws
- MM.getFrame uses provisional requestAnimationFrame implementations if possible
- TouchHandler is in the default build of modestmaps.js
- Coordinate.toKey() is clever again ;)

Thanks to @tmcw for the majority of these contributions. They were contributed
on a branch, hence only one minor version number bump. As far as we know this 
should all be backwards compatible. If we're mistaken, please file an issue at
https://github.com/stamen/modestmaps-js/issues

Note also that we've now got fairly decent node.js support for the core MM.js
classes, and there's an example of how to use Modest Maps with node-canvas to
render static map images from a tiled data source. "npm install modestmaps" for
node.js fans :)

v0.17.0
- Mouse handlers refactor: while MouseHandler is still available for adding
  all handlers to the map, double-click, zoomwheel, and drag handlers are
  available individually.
- Broken images that result from image loading errors are no longer added to
  the map.

v0.16.1
- Unimplemented abstract methods throw exceptions instead of calling `alert()`

v0.16.0
 - added MapProvider.setZoomRange for @straup

v0.15.2
 - misc syntax fixes and improve parseInt/radix correctness, from @tmcw

v0.15.1
 - switched to document fragment for loadingBay, from @tmcw

v0.15.0
 - added method chaining from @tmcw

v0.14.3
 - improve redraw behavior by ensuring layer is visible in getTileComplete
 - use a closure in v0.14.2's setTimeout to ensure proper 'this'

v0.14.2
 - add setTimeout to processQueue to avoid stack overflow/recursion
   bug in IE 7/8 (https://github.com/stamen/modestmaps-js/issues/12)
   thanks @yhahn!

v0.14.1
 - reinstated display of children for missing tiles, except when if
   map.enablePyramidLoading is set to true

v0.14.0
 - added map.enablePyramidLoading flag for pyramid loading (off by default)
 - fixed Coordinate.prototype.toKey (back to string join to avoid collisions)

v0.13.5
 - changed the order of initialization so that event handlers go last
   (this is so that attributes like layerParent are in place for complex
    event handlers like anyzoom.js... handlers can also use callbacks now)

2011-01-03 note:
 - broke modestmap.js file into src folder, now building with Makefile
 - no functionality change to modestmaps.js (just whitespace changes)

v0.13.4
 - changed to img.style.width instead of img.width, for ipads (see examples/touch/test.html)

v0.13.3
 - stubbed out tilePadding into Map.draw

v0.13.2
 - removing magic numbers from Mercator projection for parity with Python version

v0.13.1
 - rejiggered the Map's draw function to be a bit clearer
 - removed superfluous layer.coordinate (internal only)

v0.13.0
 - factored image loading out into a separate RequestManager
 - cleaned up RequestManager to be less tile-centric, more img-centric

v0.12.0
 - made callback handling more modular

v0.11.2
 - re-instated zoom level check for setExtent (fixes bug where locations are all the same)

v0.11.1
 - moved to cssText for long CSS inits

v0.11.0
 - added 'drawn' callback
 - added removeCallback
 - correctly following semver.org now, incrementing minor version!

v0.10.4
 - modified queue sorting to support pyramid loading
 - stubbed out pyramid loading
 - tidied up draw code to be clearer (wantedTiles --> validTileKeys)

v0.10.3
 - added Point.distance and Point.interpolate
 - added Location.distance and Location.interpolate

v0.10.2
 - tweak to sorting function that appears to fix an issue in IE8

v0.10.1
 - fixed tile sorting for in-between zoom levels
 - fixed tile position in onload handler

v0.10.0
 - tidied up initial coord/position maths, now supports arbitrary zoom levels (with seams)

v0.9.5
v0.9.4
 - changes to MapProvider.sourceCoordinate to support non-Mercator bounds

v0.9.3
 - added inner and outer limits to providers and enforcing min/max zoom in Map.draw()
 - changed zoomByAbout to use zoomBy (and draw/enforceLimits) before applying panBy

v0.9.2
 - fixed bug that could break zooming if setCenterZoom was called with a string

v0.9.1
 - removed assumption that layers go from 0 to 20

v0.9.0
 - added rational version numbering

May 2010, pre-semver

 + added setSize and setProvider methods (fixed the latter so that all loads are canceled)
 + optional interaction (factored out mouse handling... enables touch or keyboard later)
 + made a touch handler for iphads
 + made a TemplatedMapProvider
 + made a demo that accepts a URL template for a map provider
 + started to work towards jslint conformance
 + started to move to 80 character line length where practical
 + made a demo with two maps, synchronized
 + jslint fixes, 80 char lines, better sorting, removed createOverlay
 + templated providers wrap around in longitude by default
 + added a demo keyboard handler
 + positioning single tiles in onload instead of redrawing everything
 + added a zoom box demo
 + make sure the cache gets cleared after a while (BIG FEATURE)
 + don't load above/below north/south poles (for default mercator maps)
 + added a random subdomain helper to templated providers

