Updated changelog and documentation to include stuff we forgot to mention.
fix so that the results and summary files contain model parameters for the evaluate task.  also cleaned up printing of the featuresets in those files (in python 2).
Merge pull request #48 from EducationalTestingService/feature/fixed_outputs_to_include_params

fix so results contain model parameters for the evaluate task
Added valid options to `feature_scaling` documentation.
Merge branch 'develop' of https://github.com/EducationalTestingService/skll into develop
Added ability to run multiple experiments in a row to run_experiment
Merge branch 'develop' of github.com:EducationalTestingService/skll into develop
Merge branch 'develop' of https://github.com/EducationalTestingService/skll into feature/add_skll_converter
Added unit test for skll_convert script. Fixed bug in _megam_dict_iter
where labels for instances with all zero features were being incorrectly
set to None. Also fixed bug in _tsv_dict_iter where features with zero
values were being retained with values set as '0' instead of being
removed completely.