added COBYLA (no REST interface yet)

********* PEOPLE *************
Primary reviewer: @sc932 

Reviewers: @suntzu86 

********* DESCRIPTION **************
Branch Name: denizokt_370_constraints
Ticket(s)/Issue(s): Closes #370 

********* TESTING DONE *************
make test
make style-test
:func: actually.
```
:func:`moe.whatever.path.to.file.class.optimize`
```
you can also do :mod: for modules (files) or :class: for classes. Put a tilde like:
```
:func:`~moe.whatever.path.to.file.class.optimize`
```
if you odnt want the link to spell out the whole name (usually only applicable when you're referencing class.foo() from class.bar(), something nearby)