Restore "DstType" in AbsDiffScalarOp template arguments, even if
eventually it will be equal to SrcType

use "double" from scalar only for CV_64F input

simplify code by requesting srcDepth == dstDepth

I took the subScalar.cu code and changed the inner operation

  * modify test, too

* MulSpectrums
* StereoConstantSpaceBP
* BruteForceNonLocalMeans

to import existed CUDA stream or CUDA event to OpenCV

Conflicts:
	modules/gpu/doc/per_element_operations.rst

- Substituted HAVE_WINRT with WINRT
- Fixed compilation issues in ocl.cpp and parallel.cpp
- Fixed compiler issue for WP8: "C2678: binary '+' : no operator found which takes a left-hand - Fixed gitignore
- Added #ifdef HAVE_OPENCL to remove compiler warnings in ocl.cpp
- Used NO_GETENV similar to '3rdparty\libjpeg\jmemmgr.c;
- Added ole32.lib for core module (for WindowsStore 8.0 builds)
- Made OpenCV_ARCH aware of ARM
Signed-off-by: Maxim Kostin <v-maxkos@microsoft.com>

rename cv::cuda::internal namespace
to cv::cuda::device to prevent conflicts
with cv::internal

* remove overloads with explicit buffer, now BufferPool is used
* added async versions for all reduce functions

it might cause errors, due to implicit type conversion and another cuda::divide
overload

it is generated by CUDA headers and we can't fix it

Add Triangle method for automatic threshold computation next to the existing
Otsu's method. Triangle deals better with images whose histogram does not
contain dominant peak.

See paper Zack GW, Rogers WE, Latt SA.: Automatic measurement of sister
chromatid exchange frequency. J Histochem Cytochem. 1977 Jul;25(7):741-53.