I had to add a new function to gbuild system: set_nativeres,
because the trick in extensions/Library_npsoplugin.mk did not work.
It linked the default.res, and that made the plugin unusable under
Windows. Also, one export was missing compared to LibreOffice 3.5.

Conflicts:

	extensions/Library_npsoplugin.mk
	extensions/WinResTarget_npsoplugin.mk

Change-Id: Ib91fa2a3b72b15912587f22becccb0aebc2aa390