version 0.2
changes:
 - new json state (old cache) file
 - failed DNS updates are retried on next run
 - ip getters are used in random order, to distribute the load
 - ip get timeout
 - functional (though basic) unit testing
 - removed whatismyip.com discontinued service. added 3 others
 - some nice refactoring
unnused variable
Bug: updater was not flushing state file when domains were not updated successfully
move README.rst -> README, to avoid setup.py warning
Bug: catch timeout, raise GetIpFailed