update icons to all be 128X128, changing some GL & track event passing architecture
cleanup text stuff a bit
Create TextureAtlas class to handle grouping all textures into a single bitmap.  Adapt TextGroup to handle generic Textures, renams to TextureGroup
add TextureMesh.  Every View has a TextureMesh.
Refactor Texture drawing to use a single TextureMesh draw per ShapeGroup, with TextureAtlas mapping
fix concurrency bug in TickWindowHelper
create 'texture' package, move TextureRegion and TextureAtlases into it, rename GLText to FontTextureAtlas
Refactor ResourceTextureAtlas and FontTextureAtlas to inherit from shared TextureAtlas class
Major refactor of Icon behavior  to jive with the new texture goodness
Update button/ToggleButton select behavior
adjust icon size depending on pressed state and whether icon is present
remove MeshGroup2D, correct BG icon for add-track button
remove extraneous override in BpmView