Intercept values printing for subclasses of BaseLibLinear.
Should satisfy #155.
Merge branch 'develop' of https://github.com/EducationalTestingService/skll into feature/print_model_weights_script_should_print_out_intercept
Modified docstring on model_params to reflect my changes.
Merge pull request #163 from EducationalTestingService/feature/print_model_weights_script_should_print_out_intercept

Feature/print model weights script should print out intercept