Hook up BFGS to rest

********* PEOPLE *************
Primary reviewer: @sc932 

Reviewers: @suntzu86 

********* DESCRIPTION **************
Branch Name: denizokt_285_qei_rest
Ticket(s)/Issue(s): Closes #285 

********* TESTING DONE *************
It would be cool if we could have this if be based on python/c++ vs this one optimizer. But if that isn't clean then we can punt until the next python-only optimizer comes along.