support custom projections
First pass at the offline renderer.
Offline image layer now fetching.
Added geo to local and back routines in the top level coordinate system.  Offline rendering now working.
Sending out messages for the start and stops of all movement controls and animations.
Stickers can now have multiple images/textures and their own shaders.  Shader programs now support setting of uniform values. Found a nasty bug with multi-texture and basic drawables.
Fixed a rotation gesture problem.  Fixed a timing problem between the offline rendering layer and other... stuff.
Tweaked the timing a bit.
New start/stop handling broke test app.
Looking at read/write z buffer in loft manager.  Fixed minor bug in vector object.
Merge branch 'develop' of https://github.com/mousebird/WhirlyGlobe into develop
Was flushing too much.
Merge branch 'develop' of git+ssh://github.com/mousebird/WhirlyGlobe into develop
Finished moving screen space calculations to doubles.  This seems to help with a high level load issue.
Wasn't generating border texels for the new tile path.  Resulted in ugly mismatches along tiles.
Expose min/max vis in quad image layer.  Stickers now support a coordinate system.  Offline render layer now handles the date line.
Merge branch 'develop' of https://github.com/mousebird/WhirlyGlobe into develop
Found a potential missing context problem.
Moved screen importance calculations into their own file.  Now short circuiting importance calculation when the layer is in the same projection as the display and there's no tilt.
Exposed target level query.