Implement function patching.

I implemented basic API function patching. It is currently only possible
to patch WinAPI functions, which have been compiled to be patchable
(however, all exported functions in kernel32.dll are patchable).

Right now patching was tested with CreateFileW. Calls to that function
are correctly intercepted and logged to the debug console if available.
The wrapper calls the original implementation and returns its original
results.

In future patching may be improved to support patching of functions,
which were already patched (this is possible in case of official API
patches by Microsoft). Also, some security checks need to be added and,
perhaps, removing the patches.