lots of changes

libnotify @0.7.5: upgrade to 0.7.6
grass: multiple changes:
- move wxWidgets PortGroup usage into relevant variants
- dependencies
- configure settings
- temporarily disable building of app bundle again
- fix gem/Makefile so that it is UsingTheRightCompiler and respects the
destroot
- Make sure all substitutions are substituted in
include/Make/Platform.make
- build environment changes
- add postgresql92 and postgresql93 variants
- fix issue of wxPython being built even when not requested
- use Fortran recipe
gegl: changes to more closely match trunk
weechat @0.4.0: update to 0.4.1
xfce stack: more work on getting it to work