test the getSubmission downloads the associated file intact (PLFM-2666)
changed utils.download_file used to download locationables to use requests rather than urllib
portal endpoint should be www.synapse.org not synapse.org
added syn.getSubmissionBundles which returns a tuble of objects
fixed bad spelling
Merge pull request #140 from cbare/develop

Use requests to download_file, fix portal endpoint, add getSubmissionBundles
Code review w/ Abhi.