Moved CPrimaryScreen and CSecondaryScreen to the lib/synergy

and the platform specific implementations to lib/platform.
Added an lib/arch method to query the platform's native wide
character encoding and changed CUnicode to use it.  All
platform dependent code is now in lib/arch, lib/platform,
and the programs under cmd.  Also added more documentation.

lib/arch/CArchMultithreadWindows.h

@@ -37,6 +37,7 @@ public:
 	CRITICAL_SECTION	m_mutex;
 };
 
+//! Win32 implementation of IArchMultithread
 class CArchMultithreadWindows : public IArchMultithread {
 public:
 	CArchMultithreadWindows();