Changes

Win,GDI,SWT: Fix pfd to caps conversion. Added thorough debug code.

Debug code added for use case: WinXP-32bit, GDI, SWT,
where WGL.wglGetCurrentDC() returns a non null value which is invalid.
Using the value (hdc) on eg GDI.GetObjectType(hdc) return 0 instead of
3 (OBJ_DC) and GDI.GetPixelFormat(hdc) returns 0 with last error 2000.