Fixed cache problem.
Fixed a layer priority problem and a bug related to empty image tiles.
Fixed an animation bug.
Merge branch 'develop' of git+ssh://github.com/mousebird/WhirlyGlobe into develop
Fixed a problem with non-power of 2 textures.
Convenience methods for starting vector tiles
Changes to the icon manager to match Mapnik better.  Can now start with JSON or XML based Mapnik file.  Marker style matches Mapnik a bit better.  Added Maki icons to project.  Starting to add Mapzen vector tile source.
Can now force label to stay upright on the screen.
Allow users to set the default font used by text.  Upright text implemented in layout logic.
Cleaned up marker name logic
Partial commit
Merge
Compiling again, but not working.
Can move a single frame through the system.
All frame loading working again.
Title fix.
Fixed an opacity interpretation problem.  Now parsing rgba colors.
Merge, module cleanup
Updating submodules.
Fixed submodule reference to clipper