Makes a bunch of strings into unicode

Trying to prevent unicode decode errors.
Removes reference to lists.learningu.org

Resolves Github issue #245.
Adds de-duplication to MessageRequest.process()
Fixes CommunicationsPanelTest

As a result of the change in 20f4ec3c, some of the test emails were
being de-duplicated.  This was happening because
ProgramFrameworkTest.setUp() was creating test users with the same name
and email address (all empty strings, in fact).

This change has setUp() create test users with unique names.
Merge pull request #1335 from learning-unlimited/fixes

Improvements to dbmail