split processing of request in PRBAC middleware to class method so that it can be reused in emailed report
specifically raise PermissionDenied when dispatching the email view of a custom report so that the emailed report can catch it and retiurn an appropriate response.
make sure the request gets processed by PRBAC middleware before dispatching any reports in emailed report
catch PermissionDenied on emailed report response and return a better error message.
remove all untracked files on preindex and deploy
add celerybeat-schedule to .gitignore

also add staging.yaml for convenience
fix backwards submit history time bugs
properly escape filenames in export requests

http://manage.dimagi.com/default.asp?89954
Update readme issues found while onboarding
Merge pull request #2749 from dimagi/fix-readme

Update readme issues found while onboarding
Merge pull request #2748 from dimagi/export-encoding-fix

properly escape filenames in export requests
Merge pull request #2741 from dimagi/saved-reports-fix

Fixes Emailed Custom Reports
fix build fail with translations V2 but no translations
restore prop_names
disable save button while saving custom export
fix typo, custom_roles is a list of ids already
some earlier reminders do not have the attribute of active but default to True according to the doc
Merge pull request #2747 from dimagi/submit-history-times

fix backwards submit history time bugs
Merge pull request #2752 from dimagi/sub-changes-fixes

Subscription Change Handler minor fixes
avoid having to do an extra db lookup when getting a timezone for a user