Merge branch 'assetstore-management' into s3-assetstore
Skeleton for S3 assetstore type
Add boto write access validation for S3 filestores
refs #227. Refactor upload code into file model

(not totally complete yet, still need to move resume behavior)
Move upload resume impl to file model
Fix bug in upload resume behavior
Backend for init step of s3 assetstore
Merge remote-tracking branch 'origin/master' into s3-assetstore
Proof-of-concept single-chunk S3 upload
Get client-side progress reporting for single-chunk s3 uploads
Upload finalize step for s3 single-chunk case
Authenticated download capability for S3 hosted files
Merge remote-tracking branch 'origin/master' into s3-assetstore
Force s3 hosted files to be downloaded as attachment with correct name
Implement delete method for s3 assetstore adapter

It queues up an asynchronous deletion event. Also fixed a failing
style test.
Implement multichunk upload to S3
Fix failing tests, use explicit content-type header on s3 finalize
refs #164. Write docs about assetstores, including S3 assetstores.

- Reorganized some API docs that were out of place
- Fixed TOC bug
- User guide docs about Files
- Added first-steps guide in installation instructions
Merge remote-tracking branch 'origin/master' into s3-assetstore

Conflicts:
	docs/installation.rst
	requirements.txt
Add security auditability data to s3 file records

Also add full support for empty files in s3 assetstores