The COM components will (usually? always?) be called on the main thread
via COM, and may also be called on any thread from the UNO event
listeners.  Both ways may access the global AccWinObjectManager.
So the easiest way to lock all that without introducing new deadlocks
seems to be to just use the SolarMutex.

The fact that the main thread is in a COM STA is rather irrelevant here
since we don't currently do the required manual marshalling of the COM
pointers so they can be accessed from UNO event listeners running in
threads other than the main thread anyway.

To get that to build:
- use prewin.h and postwin.h around ATL headers
- link UAccCOM against vcl
- define both UNICODE and _UNICODE to not break on mis-matching TCHAR
  nonsense

Change-Id: I1ccdf7a4a5c2b5f0b9c29ef39d126c4b8a16898a