Improve general usability of Nautilus Trash can

The trash can needs to be worked upon. It lacks some functionality and has a few inconsistencies and not well enough thought about policies.

The following links are only meant as a reference for developors. If bundling all this seems inappropiate, feel free to delete this blueprint.

This bundles the following blueprints:
- https://blueprints.launchpad.net/ubuntu/+spec/friendly-recovery
- https://blueprints.launchpad.net/ubuntu/+spec/delete-locked-items-trash
- https://blueprints.launchpad.net/ubuntu/+spec/evaluatesecuritymeasures
- https://blueprints.launchpad.net/ubuntu/+spec/gnome-secure-trash
- https://blueprints.launchpad.net/ubuntu/+spec/gnome-trash-restore-files --> implemented in Intrepid
- https://blueprints.launchpad.net/ubuntu/+spec/trash-applet
- https://blueprints.launchpad.net/ubuntu/+spec/desktop-icons

the following brainstorm idea's:
- http://brainstorm.ubuntu.com/idea/1002/
- http://brainstorm.ubuntu.com/idea/14131/
- http://brainstorm.ubuntu.com/idea/14081/
- http://brainstorm.ubuntu.com/idea/12296/
- http://brainstorm.ubuntu.com/idea/1144/
- http://brainstorm.ubuntu.com/idea/11030/
- http://brainstorm.ubuntu.com/idea/8926/
- http://brainstorm.ubuntu.com/idea/8409/
- http://brainstorm.ubuntu.com/idea/11952/
- http://brainstorm.ubuntu.com/idea/4401/
- http://brainstorm.ubuntu.com/idea/9699/
- http://brainstorm.ubuntu.com/idea/8520/
- http://brainstorm.ubuntu.com/idea/7512/

and many bugs: https://bugs.launchpad.net/ubuntu/+bugs?field.searchtext=trash+can&orderby=-importance&search=Search&field.status%3Alist=NEW&field.status%3Alist=INCOMPLETE_WITH_RESPONSE&field.status%3Alist=INCOMPLETE_WITHOUT_RESPONSE&field.status%3Alist=CONFIRMED&field.status%3Alist=TRIAGED&field.status%3Alist=INPROGRESS&field.status%3Alist=FIXCOMMITTED