Changed fastNlMeansDenoising and fastNlMeansDenoisingMulti back to sum of sq distances. Moved sq sum of abs distances to fastNlMeansDenoisingAbs and fastNlMeansDenoisingMultiAbs

Basic 16-bit implmentation of fastNlMeansDenoising. Table-based exponetiation leads to high memory footprint and loss of precision in 16-bit mode.

This should allow many algorithms to take advantage of more parallelization
technologies.

e.g. <opencv2/core/core.hpp> become <opencv2/core.hpp>

Also renamed <opencv2/core/opengl_interop.hpp> to <opencv2/core/opengl.hpp>

Made all STL usages explicit to be able automatically find all usages of
particular class or function.

Issues #2646

* reorder arguments
* rewrite accuracy tests
* replace doubles with integer arithmetic inside the main loop

enabled SSE3 by default; integrated SSE3-optimized bilateral filter (by Grigoriy Frolov); modified API of non-local means (use Input/OutputArrays)