GNU Radio version of CMake's "UseQt4" script, which determines header (INCLUDE) and library directories, but requires that the including script add use them (via INCLUDE_DIRECTORIES and LINK_DIRECTORIES)
Tweak INCLUDE dirs such that INCLUDE_DIRECTORIES and LINK_DIRECTORIES are ordered as: internal build and source for this component, other components (internal build and source, or already installed), non-project non-system dependencies (e.g., Qt, Boost, Python), system dependencies (e.g., CoreAudio).
Merge branch 'master' of http://gnuradio.org/git/gnuradio into fix_build_dir_order
GrUseQt4 -> GrSetupQt4, since that's what it really does.
FFT_INCLUDE_DIRS -> GR_FFT_INCLUDE_DIRS, and reorder
Reorder SWIG_INCLUDE_DIRS
remove unnecessary build commands