Adding some declarations to the MAPI headers

[amtopel]

Hi, I was wondering if we could add some missing declarations to the MAPI headers, specifically these:

struct RTF_WCSINFO
{
	ULONG size;
	ULONG ulFlags;
	ULONG ulInCodePage;
	ULONG ulOutCodePage;
};

struct RTF_WCSRETINFO
{
	ULONG size;
	ULONG ulStreamFlags;
};

STDAPI_(HRESULT) OpenStreamOnFileW(LPALLOCATEBUFFER lpAllocateBuffer, LPFREEBUFFER lpFreeBuffer,
	ULONG ulFlags, LPWSTR lpszFileName, LPWSTR lpszPrefix, LPSTREAM FAR* lppStream);

STDAPI_(HRESULT) WrapCompressedRTFStreamEx(LPSTREAM pCompressedRTFStream, const RTF_WCSINFO* pWCSInfo,
	LPSTREAM* ppUncompressedRTFStream, RTF_WCSRETINFO* pRetInfo);

#define MAPI_NATIVE_BODY 0x00010000
#define pidExchangeXmitReservedMin 0x3FE0
#define PR_INTERNET_CPID PROP_TAG(PT_LONG, pidExchangeXmitReservedMin - 0x02)

I'd make a pull request, but I'm not exactly sure where or how these things should be properly declared. Thanks.