Remove unused variable
Always free WebGL resources in post render
Don't try to overload method return type
Remove rarely-used logger
Remove stale FIXMEs
Hide canvas when map is not defined
Add missing instance variable declaration, thanks @elemoine
Merge pull request #111 from twpayne/webgl-renderer-clean-ups

WebGL renderer clean ups
Merge pull request #112 from twpayne/dom-renderer-clean-ups

DOM renderer clean ups
Implement view hints architecture
Set panning hint in DragPanInteraction
Don't remove tiles while panning
Add animating hint
Clone hints array so that pre-render functions can modify it
Make animations set animating hint
Don't remove tiles when animating
Merge pull request #110 from twpayne/interaction-hints

Interaction hints
Move pixel/coordinate matrices into frame state, remove canRotate
Move common event handlers into base class
DOM renderer should re-render when layers are added or removed