Set a new cache thread that constantly updates the ticket cache.

- This thread locks the cache object (dictionary) everytime it
  updates it.
- TicketCreateThread will update the cache object (prior locking)
  whenever a new ticket is created.
- A new 'noop' option is added to RT's parameters which will allow
  to execute the app without performing the POST operations (create,
  edit, ..)
Merge pull request #12 from orviz/ticket_cache_as_shared_queue

Set a new cache thread that constantly updates the ticket cache.