index.js Emit ready event, when db connected

Emit ready event. I work with gridFs, and i need MongoDb object(MongoJS.client)
Merge pull request #98 from RG72/patch-1

index.js Emit ready event, when db connected
Avoid getIndexes crash when called with no parameters.
Merge pull request #101 from sorribas/master

Avoid getIndexes crash when called with no parameters.
Merge branch 'base'