Reconcile finder options for count and find

[squeejee]

Finder methods currently sanitize the conditions hash and map an array to a Mongo $in condition. The count method with the same arguments does not do this.

Finder options might be too heavy for count. Should we make convert_conditions public so we can call it in the count case?

[jnunemaker]

Yeah, I ran into this too. I'll come up with a solution and push it. I have some ideas.

[jnunemaker]

Implemented more thorough use of converting find conditions and options to mongo criteria and options. losed by 6f161df.