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 *************
you never use either of these
additionally, these don't really capture the actual behavior in the code. You choose the default optimizer based on the value of q in qEI, not analytic vs monte carlo.