change triggermanager synchronization to use the same lock object as the
scanner thread
scanner thread does syncObj.wait while waiting
add better description of sla triggers
add orphan process clean up script
minor change to make everything of scanner thread wrapped inside a big
sync block
Merge branch 'master' of github.com:azkaban/azkaban2
added test case to mimick the deadlock that happened when
TriggerScannerThread is processing all triggers, some of them try to
insert new triggers, and another thread also tries to insert trigger
into the system
delete the orphan process cleaning script as its usefulness is unclear
and people could write up their own script if the orphan processes do
appear
Merge pull request #118 from cjyu/master

clean up trigger scanner thread sync blocks and add orphan process sweeping script