Criteria options in mongoose read method

Hello, 
Thank you for this library. 
This little modification will permit to add search criteria in the read method of mongoose middleware. 
It will be useful in the backboneJS.fetch method for example because it will handle the "data" parameter.
http://backbonejs.org/#Collection-fetch

Best regards
Merge pull request #59 from yanno/patch-1

Criteria options in mongoose read method