check for counters flag
pep8 pass
increment counters if we are using them
pep8 pass
test for switching to counters
truncating + tests
tests for truncate_at limits
Merge branch 'develop' into feature/issue-675-expire-message-store-cache-keys
adding use_counters bool flag to batch_start() and split out tests
put `cache` in function names and add deprecation warnings
removing switch_to_counters() call from batch_start() (thanks @hodgestar)
yield batch_start() all for real redis
Merge branch 'feature/issue-675-expire-message-store-cache-keys' into develop
Merge branch 'develop' of github.com:praekelt/vumi into develop