FIXED: Circuits in CIRCUITS_HISTORY were not removed after HISTORY_DURATION seconds
CHANGED: The way things were trimmed from lists (LINKS_BLACKLISTED, CIRCUITS_HISTORY)
Before recurrent events (usually each minute) would check to see if any items in those lists
would need to be removed. Now, a timer is attached to each item in those lists,
removing the need for periodic checks over potentially many items. It also makes
sure that items are removed at the correct interval instead of waiting for a pass
of the recurring event.
CHANGED: Stress test now does multiple checks at each step in the circuit lifecycle
from circuit request, switching to online, switching to offline and eventually
event getting removed from CIRCUITS_HISTORY alltogether

Commented out the test in do_all_tests since it's a 60min test...