ability to create a single filehandle, and explicitly set it's content type. special logic to support code file preview generation (recognize by file extension)
Merge branch 'develop' of https://github.com/Sage-Bionetworks/Synapse-Repository-Services into develop
add zip preview test
from code review
cleanup
Merge pull request #337 from jay-hodgson/develop

SWC-248: Generate appropriate previews for all leaf entities