Apache Forrest code add

code add
by
DC
:

Added new "clean" targets. Doing 'forrest clean-site' will remove
the contents of the project's generated documents directory.
Doing 'forrest clean-work' will remove the project's work directories
(usually build/tmp and build/webapp which include the Cocoon cache
and the Cocoon logs).
Doing 'forrest clean' will remove both sections.