added logging to the Action and Condition classes and implemented a basic psr3 log interface and log level class

errors during claiming next item, refactored so that next item is the one with the oldest release time

issue with group contact cache resulted in a deadlock whilst checking a condition. Refactored checking of group membership so that the group contact cache is not used

condition added for issue #23, to be tested on MAF as there is no core way to add recurring contribution