This commit adds the non-courseware lms/djangoapps and lms/lib.

These keys are now objects with a limited interface, and the particular
internal representation is managed by the data storage layer (the
modulestore).

For the LMS, there should be no outward-facing changes to the system.
The keys are, for now, a change to internal representation only. For
Studio, the new serialized form of the keys is used in urls, to allow
for further migration in the future.

Co-Author: Andy Armstrong <andya@edx.org>
Co-Author: Christina Roberts <christina@edx.org>
Co-Author: David Baumgold <db@edx.org>
Co-Author: Diana Huang <dkh@edx.org>
Co-Author: Don Mitchell <dmitchell@edx.org>
Co-Author: Julia Hansbrough <julia@edx.org>
Co-Author: Nimisha Asthagiri <nasthagiri@edx.org>
Co-Author: Sarina Canelake <sarina@edx.org>

[LMS-2370]

Add in unicode handling for names.

Add tests for various error mail sending scenarios

Add manual transaction handling.

Remove grandfather option

Clean up common.

Add the ability to dry-run the command without sending e-mail.

Don't save courses sent during a dry run

Switch to EmailMessage for LinkedIn so we can send HTML emails

Update subject copy.

Use correct name for CertificationName

Fix up certificate url information.

Fix whitelist logic to handle empty lists.

We were using to indicate the date a course ended.  Better to remove it,
since edX certificates don't really expire.

Refactor findusers script to be fully lazy, in hopes we don't run out of memory with huge numbers of users.