Make ShareRoom item details URL into an active link.

This is a provisional solution for #505, so that people can tap the link
to get to the ShareRoom, and copy the URL from there. Soon @devgeeks
will integrate the long-tap copy plugin, but this will provide an
alternative until then.
Merge pull request #511 from SpiderOak/issue-505-shareroom-urls-as-link

Make ShareRoom item details URL into an active link.
Issues #507 and #514 - advanced login link and no server prompt

- Removes initial server prompt
- Adds "advanced login settings" link (calls the `setInitialServer` function from the removed prompt)
- Adds a "Learn more..." link to the login screen when the preliminary screen is disabled
Tweaked to get the correct value for `s("SpiderOak")`
Merge pull request #515 from SpiderOak/issues-507-and-514-adv-login-link-and-initial-server

Issues 507 and 514 adv login link and initial server
Respond to empty username and password like any incorrect credentials.

(One might ask why the web API responds to an empty username and
password with a 200, but we already know the web API is, peculiar.)
Merge pull request #516 from SpiderOak/issue-509-empty-login-credentials

Respond to empty username and password like any incorrect credentials.
Name package branding script to something more informative.
Clear the login password field as soon as we've stashed the value.

While we're at it, clear the ShareRooms password field similarly -
unnecessary, since we don't return to the form, but more consistent, in
case we ever do return there.
But don't clear the login password if it wasn't really tested.

Ie, don't clear on temporary server failure or authentication
interrupted.

The process of fetching a ShareRoom doesn't have such discrimination, so
we clear whenever the fetch of a password-protected password fails.
Merge pull request #518 from SpiderOak/issue-513-clear-failed-password

Clear the login password field as soon as we've stashed the value.
Merge branch 'master' into issue-468-package-configuration