added additional tests for gpu filters
fixed gpu features2D tests

fixed some bugs in gpu module

refactored tests for them

fixed several warnings

lot's of changes; nonfree & photo modules added; SIFT & SURF -> nonfree module; Inpainting -> photo; refactored features2d (ORB is still failing tests), optimized brute-force matcher and made it non-template.

wrote more complicated tests for them
implemented own version of warpAffine and warpPerspective for different border interpolation types
refactored some gpu tests

updated gpu tests for CornerHarris and CornerMinEigen
moved direct convolution implementation to gpu::filter2D, gpu::convolve now use only DFT-based algorithm (Bug #1639)

fixed HaarCascadeLoader test (incorrect behavior due to macros usage)

removed void integral(const GpuMat& src, GpuMat& sum, GpuMat& sqsum, Stream& stream) - it fails with NPP_NOT_IMPLEMENTED error
updated docs, accuracy and performance tests

now it supports kernel's size up to 32

minor build system changes (now cuda code in opencv_core is compiled using CUDA_ARCH* cmake variables)