Refactoring emerson model class and optimizers to use unified objectives and algorithms
adding dual decomp to emerson
working refactor
Merge branch 'emerson_refactored' of https://github.com/pbailis/spark into emerson_refactored
fixing a bug
Merge branch 'emerson_refactored' of https://github.com/pbailis/spark into emerson_refactored
minor reformatting
merging with upstream