Added getResolver()

I had to do some crazy shit to get Illuminate using an existing PDO connection:

http://d.pr/i/5Joy

This method made that just a little bit easier.

I would however like to see a "reuse" method to wrap this logic up. Then anyone with a PDO connection can add some Eloquent to it, without needing a 2nd connection.
Merge pull request #3 from philsturgeon/patch-1

Added getResolver()