changed: get rid of DATAPATH definition

rather ask XBMC for path on runtime
[add] ProjectM icon
switch to deps.txt for addon dependencies
disable docs in ftgl depend
fix FindProjectM.cmake handle_standard_args
use pkg-config to detect GLEW and freetype and use shared projectm
set PKG_CONFIG_PATH if passed in via -DPACKAGE_CONFIG_PATH
[linux] copy libprojectm.so to addon libdir