decklink: Windows support
See attached patches. My test machine is having other issues preventing me from doing full testing of the modules but for all appearances this should be working. It compiles, loads, and detects cards. DLL module (compiled in VLC 2.1.x tree) included for testing.
DeckLinkAPI.h and DeckLinkAPI_i.c are generated from Blackmagic DeckLink SDK 10.1.4/Win/include/DeckLinkAPI.idl using: set PATH=%PATH%;"C:\Program Files (x86)\Microsoft Visual Studio 12\VC\bin" midl /I "C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Include" /win32 /h DeckLinkAPI.h DeckLinkAPI.idl
I tried to do the same using widl but got Segmentation faults, so I've included the midl-generated files in the patch.