Update gtk-mac-bundler from 0.7.3 to 0.7.4 - make gtk3-demo work

[fredowski]

There is a new version 0.7.4 of gtk-mac-bundler in upstream. I updated the portfile to use the new upstream version.

I tried to create an app bundle for the gtk3-demo that is part of the examples. I tried to create the example directly from the macports installation without the jhbuild environment. For this purpose I added

• a patch to add the changes between 0.7.4 to the git version from February 2016
• a patch for bundler.py for the charset.alias as in the previous macports version
• a patch for examples/gtk3-demo.bundle to produce the bundle from macports
• a patch for examples/gtk3-launcher.sh to start the application.

• a change in the portfile to copy the examples to /opt/local/share/gtk-mac-bundler/examples
• a change in the portfile to modify the prefix in examples/gtk3-demo.bundle

With these changes I can produce the gtk3-demo application directly from the macports environment via

gtk-mac-bundler /opt/local/share/gtk-mac-bundler/examples/gtk3-demo.bundle