fix secondary sorting in MongoCluster
Merge branch 'master' into develop
add config options and lookup mongoctl location
update config handling

- manage config path in one place
- make mbs config option more mongoctl like
- add option to set mongoctl config directory path
Merge branch 'master' of github.com:mongolab/mongodb-backup-system

Conflicts:
	mbs/strategy.py
Merge branch 'master' of git://github.com/gregbanks/mongodb-backup-system into gregbanks-master