clarified parameters inputs and outputs at the interface level for better clarity and ease of use, also corrected a mistake at activateContoursProcessing interface method

[+] Color conversions stub via pixel types
[+] Pyramid calculation (required for mipmaps in CUDA 4.1)
[~] Changed C strings to C++ throughout NCV
[~] Fixed a couple of bugs in NCV

Now developers should call the method setFaceDetectionMaskGenerator() to use prefiltering mask generator
implemented for face detection.