initial draft for libfreenect2 api based on libfreenect api
removed several functions, which complicate current implementation; added functions to support ir intensity frames
explicitly link in pthread on Linux/MacOSX
Merge pull request #20 from floe/cmake_fix

explicitly link in pthread on Linux/MacOSX
Merge pull request #12 from christiankerl/api

initial draft for libfreenect2 api based on libfreenect api