Implement GAppInfo on OSX

This is an implementation of most of GAppInfo using the OS X
NSBundle APIs.

Missing at this point are things that don't have equivalents
in OS X, such as hidden desktop files, last-used, manual type
associations, and g_app_info_get_all().

https://bugzilla.gnome.org/show_bug.cgi?id=734946
5 files changed