Merge pull request #526 from brucehoff/SWC-651

SWC-651
400-level error for evaluation name conflict
PLFM-1974: API to retrieve Files from Submissions
code review changes
Merge pull request #529 from bkng/develop

PLFM-1974: API to retrieve Files from Submissions
fix for SWC-651
SWC-651
Merge branch 'release-2' into develop
Merge branch 'develop' of https://github.com/Sage-Bionetworks/Synapse-Repository-Services into develop