Bug 865058: Add order field to newsletters

Add an `order` field to newsletters. Bedrock already has code on the
newsletter preference center page so that if the newsletters include
an `order` field, they'll be sorted by that for display, instead of
by the title.

Also update the admin config to make it easier to work with the order
fields, by making them editable right in the display list.  Add a
few other fields to that for good measure.
Fix no lang on new user in some cases

If we were creating a new ET user in update_user, and
whatever form they submitted didn't have a lang included,
we were ending up passing a None lang to send_welcomes.
Merge pull request #60 from dpoirier/new-user-no-lang
Bug 892585: Send text confirmation notices

Regression - was not adding _T to message IDs for
confirmation notices when user preference was text.
Merge pull request #62 from dpoirier/text-confirmation-notices
Merge pull request #49 from dpoirier/bug-865058-order-newsletters
Remove unused basket apps and files

This is the first step in cleaning up basket. It aims to remove
unused apps and files, but make the minimal other changes needed
to continue working, to make this set of changes feasible to
review.
Merge pull request #48 from dpoirier/remove-unused-apps
Use nose, since we have it installed already anyway
Move `news` app up to top level

And make a few related edits elsewhere (not many, though)
Merge pull request #63 from dpoirier/use_nose
Improve project README and move news app info to README.
Merge pull request #65 from pmclanahan/improve-readme-docs

Improve project README and move news app info to README.
Enable support for Travis CI.
Change Travis to use MySQL for tests.
Add flake8 checking to Travis CI.
Issue #42: Refactor basket tests

Break basket tests out from a single, humongous file into a bunch of
files, none over 1000 lines long and most much shorter than that.
Merge pull request #66 from dpoirier/feature/42-refactor-tests

Issue #42: Refactor basket tests
Bug 823987: require double opt-in for EN newsletter subscriptions

* Don't use language to exempt any subscribers from having to confirm
* Add a field to basket newsletters to allow them to specify a message
  to use for confirmations
Merge pull request #61 from dpoirier/bug-823987-en-double-optin

Bug 823987: require double opt-in for EN newsletter subscriptions