Trash is back

Because this feature was requested quite often, and it somewhat makes sense for a file manager, I'll add trash support (based on the trash specification) for the next release (most probably RC1).

Trash support will be transparently available to all applications using thunar-vfs (no API/ABI breakage, just a few special methods added), and it should be easy to develop a panel plugin that displays the trash can or add a trash can to xfdesktop.

Unfortunately the problem of interoperability of trash:-URIs remains, but that should be a minor problem as long as people don't try to use the trash as primary storage for their documents.