better prevention of recursive force_state_refresh
now ObselCollection's need force_state_refresh to recompute
http_server force_state_refresh on the resources it serves
now all ObselCollection's accept the 'quick' parameter

(not just ComputedTraceObselCollection)
iter_obsels now forces a state_refresh (unless quick is set)
methods now assume that the sources are fresh

and so bypass force_state_refresh by using 'quick' whenever possible
added debug logs to lock.py
improved lock management
improved stress-ktbs, added option for forking multiple processes
ensured one retry in httplib2 connections
added example uWSGI configuration file
made WithLockMixin dependancy explicit