[PAXWEB-549] Concurrency issues with the war extender
[PAXWEB-548] Pax-web can sometimes be stuck waiting forever for a servlet to initalize

I think the only possibility to have the servlet not being initialised is if the internal jetty server is stopped, which should be cause the loop to wait forever.
Fix some javadocs
[PAXWEB-550] Remove superfluous errors when unregistering a web app
[PAXWEB-551] Shutting down web applications does not correctly clean objects
[PAXWEB-552] Make servlet context handler have a more meaningful display name