Rename 'RB'(renderbuffer) to 'RBO'(renderbuffer object)
Thanks to the ID abstraction, we can use proper overloading now!
Rename 'Tex' to 'TEX' for consistency
Document gl-util types
Move draw order sorting into SceneElement
Undef utility macro in header
Only require EXT framebuffer extensions
Use EXT version of gl functions
Remove 'Default' FBO binding (only allow 'Read' and 'Draw')

Also make code more verbose by removing default mode
parameter value to 'FBO::bind'
Fix wording
Free SDL surface if 'TexPool::request' throws
Fix Plane not accepting nil for '#bitmap='
Forgot some EXT functions
Pack REQUEST event codes into enum
Rename constant
Spacing
Add 'Makefile' / xxd+ binary to gitignore
Properly free RWops associated with Font objects
Catch errors that could happen when reading Scripts.rxdata
Add FIXME