Fix error in GTK_PYTHON_CHECK which prevented building python bindings.
Remove doc reference to a file that generates no docs.
Release gtk-mac-integration-2.0.6
Bug 739492 - Default key binding for hiding window on OS X does not work.

Add GtkAcceleratorGroup with accelerators for Hide and Hide Others so
that Gtk can process them when quartz isn't handling the accelerators.
Add protocol designator to GtkApplicationDelegate declaration.

Hoped it would silence the incompatible type warnings, which it didn't,
but it seems the right thing to do anyway.