Adding support for WinRT(WinPhone 8/8.1 and Win Store) via CMake 3.1

- 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>

modules/core/src/parallel.cpp

@@ -69,7 +69,7 @@
     #define HAVE_GCD
 #endif
 
-#if defined _MSC_VER && _MSC_VER >= 1600
+#if defined _MSC_VER && _MSC_VER >= 1600 && !defined(WINRT)
     #define HAVE_CONCURRENCY
 #endif
 
@@ -458,7 +458,7 @@ int cv::getNumberOfCPUs(void)
 {
 #if defined WIN32 || defined _WIN32
     SYSTEM_INFO sysinfo;
-#if defined(_M_ARM) || defined(_M_X64) || defined(HAVE_WINRT)
+#if defined(_M_ARM) || defined(_M_X64) || defined(WINRT)
     GetNativeSystemInfo( &sysinfo );
 #else
     GetSystemInfo( &sysinfo );