Rename submitted files when a new codename is generated
Improve error handling, and neaten rename functionality by using a regex.
Merge pull request #581 from DonnchaC/rename-submission-designation-change

Rename submitted files when a new codename is generated. Fixes #557.
Logo links to lookup view if source is logged in

Currently, the logo always links to the index. This is a little bit
different from the standard web UX, where such a "home" link takes a
logged in user to their user-specific home page. I'm concerned that the
current behavior may lead to users being locked out of the account they
just created if they accidentally click it without having memorized or
recorded their codename.

This change checks if the user is logged in, and if so, makes the logo
link back to their lookup page, where they can make submissions and
receive replies.
Remove request_that_secures_file_uploads

This was an example integration for a proposed mitigation for the
"plaintext remains in memory" issue (#99), from when we were trying to
solve it by replacing the underlying stream class used by Flask for
requests. Now that we have a better solution that doesn't require
monkeypatching so much Python, this is no longer needed.
Merge pull request #600 from freedomofpress/source-interface-logo-link

Logo links to lookup view if source is logged in
Merge pull request #601 from freedomofpress/remove-request-that-secures-file-uploads

Remove request_that_secures_file_uploads
Fix deleting replies on journalist interface
Remove double test of reply sending
Merge pull request #603 from DonnchaC/fix/journalist-delete-replies

Fix deleting replies on journalist interface
Fixup log message so it's properly generic
basic journalist login with username/password
Add "is admin" flag to Journalist
Add view decorator for admin-only pages

* clarify similar code in login decorator
* stash logged in user in `g`
basic admin interface with crud for Journalists
add users from admin interface
add timing metadata to journalist users for auditing
Use exceptions for login error handling
admin users automatically go to admin index
function to set password for Journalists