Use validity extent to generate default resolutions

Previously, the TiledWMS source generated a resolutions array
derived from the world extent in meters, to match the default
Web Mercator resolutions of the map. This wouldn't work for
projections with distance units different than meters. It is
better to commit to a default resolutions array where zoom level
0 is the validity extent of the projection (not the Web Mercator
world extent!) at a 256 pixel tile size.
Refactor mouse position control to use postrender event
Update mouse position on each frame
Merge pull request #118 from twpayne/mouse-position-control-refactoring

Mouse position control refactoring
Update Bing maps key
Merge pull request #91 from elemoine/bingkey

Bing maps key will expire on 15 Jan 2013
Add ol.Rectangle.extend
Merge pull request #114 from ahocevar/resolutions

Use validity extent to generate default resolutions. r=@twpayne,@elemoine
Refactor attribution control
Add default tile size @define, refs #114, fixes #120
Factor out updateTileUsage
Ensure DOM element is removed when layer is removed
Upgrade to latest version of pake
Only run gjslint on modified files
Remove removeLayer, thanks @fredj
Merge pull request #125 from twpayne/build-clean-ups

Build clean ups
Merge pull request #124 from twpayne/dom-renderer-layer-remove

Ensure DOM element is removed when layer is removed
Merge pull request #121 from twpayne/attribution-control-refactoring

Attribution control refactoring
Merge pull request #122 from twpayne/default-tile-size

Add default tile @define, refs #114, fixes #120
Add canvas checks