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/CArchStringWindows.cpp

@@ -36,3 +36,9 @@ CArchStringWindows::~CArchStringWindows()
 #define HAVE_VSNPRINTF 1
 #define ARCH_VSNPRINTF _vsnprintf
 #include "vsnprintf.cpp"
+
+IArchString::EWideCharEncoding
+CArchStringWindows::getWideCharEncoding()
+{
+	return kUTF16;
+}