Pulled out mvndst parameters

********* PEOPLE *************
Primary reviewer: @sc932 

Reviewers: @suntzu86 

********* DESCRIPTION **************
Branch Name: denizokt_376_fixflakes
Ticket(s)/Issue(s): Closes #376 

********* TESTING DONE *************
make test
make style-test
made sure demos and pretty endpoints still work
i'd leave this at even 2 or 3 unless it really slows things down (e.g., in case an objective has some weird state whose effects aren't seen in just 1 query)