Added active objects, for editing.  Working on font texture manager and new label rendering.  Moving some of the builders out into their own modules so the active objects can use them.
Selection logic moved into its own manager so it can be called from more than one thread.  Added an explicit find object at location method.  Font texture manager now working, but more to do.
Messing with cache policy
Nearly finished with texture based fonts.  Moved font manager into the scene.
UIScrollView compatibility and orthogonal top down view support.
Starting on tile source wrapper.
Updates to the active models in the component.  Dynamic drawable atlas now supports custom shader programs.  Fixed a culling bug that caused dynamic drawables to randomly disappear.  More support for font based labels.
Moved add layer functionality out into init/alloc and add calls.
Added support for external tiles at the Component level.
Added enable to regions in big drawable.  Lets us turn things on and off. A few efficiency improvements related to screen space calculations. Chunk layer using enables in drawable atlas.
Added quad paging layer.  Added a few view controller add methods that are thread safe by passing in the description dictionary.
Added heading control.  Added active screen marker object.  Fixed a timing problem in the chunk layer.
Deprecated some non-thread safe methods.  Adjusted the test program accordingly.  Fixed a display problem in chunks.
Fixed a shader bug.  Tweaking the number of simultaneous tiles.
Merge branch 'develop' of https://github.com/mousebird/WhirlyGlobe into develop
Interaction with scroll view working properly.  Cleaned up a few strong references.
Cleaned up the tethered interface a bit.
Cleaned up a scene teardown problem.  Cleaned up the scroll view observing code.
More modernization of the object interfaces.  Selection manager wasn't working right.  Fixed.
Merge branch 'develop' of git+ssh://github.com/mousebird/WhirlyGlobe into develop