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

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

 [~] Automatically tracked dependencies between modules
 [+] Support for optional module dependencies
 [+] Options to choose modules to build
 [~] Removed hardcoded modules lists from OpenCVConfig.cmake, opencv.pc and OpenCV.mk
 [+] Added COMPONENTS support for FIND_PACKAGE(OpenCV)
 [~] haartraining and traincascade are moved outside of modules folder since they aren't the modules

Added warp method into the RotationWarper interface, added find() into VoronoiSeamFinder which uses only source image sizes

fixed bug in opencv_stitching (corrected resize images step), added matches checking (both 1->2 and 2->1 must be presented)