make install: Install files to pkgdir

 * Files should not be installed directly
   into $(datadir), but instead into
   $(pkgdir), otherwise lintian will throw
   an error.
 * This patch installs tilda.glade into
   $(pkgdatadir) instead of $(datadir).
 * It also changes wizard.c to load
   tilda.glade from PKGDATADIR instead of
   DATADIR.
Update the change log for 1.1.7
1.1.7