fix possible division by zero in ccdemos/common_ply.h
don't use DEFS variable in makefiles, just add it to CCFLAGS
compile float version of libs with -fsingle-precision-constant
demos/ModulePath
demos/*.png
demos/kdtree.obj
ccdemos/*.png
ccdemos/spheres_shadow
ccdemos/realtime
ccdemos/realtime_dragon
ccdemos/realtime_bunny
models/bunny
models/happy
models/dragon
bin/*