Merge branch 'master' into case_multimedia

casexml update since that sub is what this heavily depends on

Conflicts:
	requirements/requirements.txt
	submodules/casexml-src
fixing hq case multimedia tests

casexml's test keys changed, updating to reflect it
changing case attachment api to be login_or_digest

needs digest for ota_restore retrieval as per case attachment spec
Merge branch 'case_multimedia' of github.com:dimagi/commcare-hq into case_multimedia
Merge branch 'case_multimedia' into staging2

Conflicts:
	submodules/casexml-src