standardize all sdk methods to take in a parameter object

Summary:
some sdk methods were taking in individual parameters, and some were taking them in as a dictionary of params.
standardize all to a dictionary of params.
why: standardization + no need to change method signatures in future

todo: docs update in main branch

Reviewers: mike, ben

Reviewed By: ben

Subscribers: ben

Differential Revision: http://phabricator.bitgo.com/D398