BUG: Fixed modules to set FOO_FOUND when both headers and libraries are found.
BUG: FindSDL now has flag it responds to so it will not find/link against SDLmain. This is required to build libraries instead of applications since they don't have main(). ENH: All modules have a predictable search order, where environmental variables are searched before system paths. This is designed to make automation easier for those that need to automatically build projects without intervention but may be using alternative install locations for isolated testing. ENH: New modules for OpenSceneGraph, Freetype, GDAL, Lua, QuickTime, GIFLIB, Producer, OpenThreads. STYLE: Added documentation explaining peculuar SDL_LIBRARY_TEMP variable in SDL module when library find is incomplete.