allow labels to be placed across tile edges

`"symbol-avoid-edges": true` can be used to let labels cross tile edges
remove composited layers, ref #523
Updated docs/_layouts/default.html
Merge pull request #688 from mapbox/crosstile

allow labels to be placed across tile edges
Examples

* Add interactive: false example. Fixes #710
* Add flyTo example. Fixes #708
* Add navigation example. Fixes #709
Mouse position demo. Fixes #712
Fix permalinks
Make fly button bolder
Merge branch 'remove-composited' into mb-pages

Conflicts:
	CHANGELOG.md
	js/render/painter.js
Stop dblclick on navigation so the map does not pan. Fixes #715
fix interactivity for geojson layers
Updated docs/_layouts/default.html
fix geojsonwrapper tests
Remove needless rounding
Re-pin mapbox-gl-style-spec

Please leave pinned and update when needed; unpinning results
in more frequent build breakage.
Pin jshint
Load TileJSON; support inline TileJSON sources

Fixes #535
Fixes #698
Refs https://github.com/mapbox/mapbox-gl-style-spec/pull/143
Refactor; add tests
Update API.md
Revert _updateTiles change

This line prevents loading tiles for unused sources.