Added replication_lag
Get replica status only if replica member
Removed duplication
Formatting
replace state with stateStr
Extracted admin_database, server_status, replica_status from monitor()
Added mock for replication_lag
Removed test for mongo client connection
Refactored mongo test to be mocked
Removed travis dependency for MongoDb
Changed replication_lag to 3 sec
Compare with known value; fixed bug
Bumped version to 0.5.3
Merge pull request #66 from kris-lab/issue-66

Mongo: add replication lag metrics