Added actions to manage modules (manually adding/removing symlinks for now).
simple form for enabling/disabling owncloud module
Make module manager work for any available modules.
Combined module management actions into a single file, so it should be easier to add new optional modules.
Instead of a separate page and form classes for ownCloud module, just need one class that does both.
Added notes to the first connection design.
Properly use bcrypt:

- Don't crypto: use a library provided time-independent comparison.

- Document details about max password length and other caveats.
Fix Lintian error: unsafe symlinks exist only while testing.

We only need these actions during test time, so create symlinks to
them before running the tests and remove them after testing:

- actions/echo: /bin/echo

- actions/id: /usr/bin/id
Merge pull request #59 from jvalleroy/module-manager

Merge: James Valleroy's Plinth Module Manager
Only redirect Plinth requests to HTTPS.

Previously, we redirected all requests to HTTPS.  Now, we redirect
only when the user tries to connect to the Plinth site.
Merge upstream.
Add link to jwchat.