* force TZ to GMT as tests expect it

  so we don't need to check it in commit code

  the former conflicts with RTIR's built-in SLAs

* reimplement SetStarts action using new API

** so it's now in one row with lib/RT/Queue_*.pm...

** pretty long name, but descriptive
** returns returns txn that should be used as starting point
   for response deadline calculations
* don't treat Owner as requestor even if he is

** made a decision on one questionable item

  attention to it and comment :) while we're hacking on tests
  and implementation of other things