PLFM-1731 - add external URLs to provenance
merge upstream changes
small test change
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
Split NodeTreeDao into NodeTreeQueryDao and NodeTreeUpdateDao
Update from origin develop
PLFM-1782
cleanup
Merge pull request #337 from jay-hodgson/develop

SWC-248: Generate appropriate previews for all leaf entities
Merge pull request #339 from brucehoff/develop

PLFM-1782
Remove getLca() from the manager
Merge pull request #341 from eric-wu/develop

Split NodeTreeDao into NodeTreeQueryDao and NodeTreeUpdateDao
Added URL validation
Merge pull request #334 from dburdick/develop

PLFM-1731 - add external URLs to provenance