Merge branch 'master' into tagging

Conflicts:
	requirements.pip
Update uuid after mongo record save
oauth2 provider support for restframework
documentation on oauth2 with formhub api
update api docs
upgrade packages during deployment
Merge pull request #1247 from modilabs/tagging

Formhub API: Tagging functionality
Merge branch 'master' into oauth2
restrict xform queryset to public forms or forms shared with if requesting user is different
test different user access to form list
Merge pull request #1230 from modilabs/case_insensitive_urls

Permission check on user object rather than username - fixes #1178
changed to Pillow and set htmtmock to >= 1.0.6
test using mysql db on travis
refactor create mysql db in travis config
remove hard coded test values
pass an XForm object to the XFormSerializer
remove hard coded test values
remove _id from result set, varies depending on the database - complicated to replace the value for each row accurately
created_on does not work as expected with mysql - mysql microsecond precision is not supported yet https://code.djangoproject.com/ticket/19716
Revert "created_on does not work as expected with mysql - mysql microsecond precision is not supported yet https://code.djangoproject.com/ticket/19716"

This reverts commit dae53f52f18e23beb72fb50c62ed9c25bcd10370.