"#error" requires DOS line endings (or fails with fatal error C1004: unexpected end-of-file found)
See: http://connect.microsoft.com/VisualStudio/feedback/details/794991/c-error-directive-and-unix-line-endings-leads-to-an-unexpected-end-of-file
So replace them to #pragma message.

Support functions from OpenCL 1.1 / OpenCL 1.2

WITH_WINRT -> ENABLE_WINRT_MODE;
Some temporary char* replaced with Ptr<char>;
Build fix for regular WIN32;
Windows Platform SDK and MSVC search added to cmake;
Warinig fixes.