Added FindLibUsb and FindTurboJPEG cmake files, to search for the respective libraries, instead of hardcoding in a sub depend folder.
Added FindGlew as the one shipped with cmake only works on linux and has no GLEW_ROOT_DIR to set in enviroment variables.

Only testet on windows.
added libfreenect2/config.h defining all platform and build configuration dependend macros; fixes #100, includes #69
Merge remote-tracking branch 'christiankerl/generate_macro_header' into develop
Changes need to work