Add kwargs in jenkins, Requester, api methods

Also: Add job.build_iter method for iterating over build
Cleanup build.py
Simplify jenkinsbase.py
Simplify views.py
Add comments to artifact.py
Add kwargs to jenkinsapi methods to pass through Requests params

Add utility functions to get jobs; fix up example code
Simplify fingerprint.py
Cleanup build.py
Update setup.py to include all test requirements
Build self.get_[down,up]_stream_jobs on self.get_[down,up]_stream_job_names
Implement job.get_params_list with list comprehension
pep8 fix for Kerberos Requester
Reorder imports in build.py
Update comments on return type for get_[down,up]stream_builds
Calculate self.get_jenkins_obj once per method call (not in loop)