Removed more files.
Fixed file naming inconsistencies.
Added additional abstraction around OpenNI wrapper data types.

This should allow switching between OpenNI 1/2 wrappers.
Fixed CMake compiler flag test on Windows.
Fixed setting CXX flags and MSVC version checks.
Added command to copy OpenNI2 redist folder to bin directory.
Added OpenNI2 library checks when building.
Added OpenNI 1.x/2.x switches.
Masked oni_grabber errors when the OpenNI 1.x wrapper is not used.