Removes PE trash functionality

Removes occurences of 'trash', 'recycle bin', and 'recycle_bin' ignoring
files affected by the planning element controller removal.
Merge branch 'feature/rails3' into feature/remove_recycle_bin

Conflicts:
	app/controllers/api/v2/planning_elements_controller.rb
Adds cukes testing work package deletion
Implements destroy for work packages controller
Corrects deletion link
Merge pull request #370 from opf/feature/remove_recycle_bin

[FEATURE] Remove PE trash functionality