Enable migrations as required by Django 1.8+ ...

Django 1.8+ won't let an app without migrations depend on django.contrib.auth
models, which is migrations-enabled. Django will create the legacy tables first
and there will be a database error.
This commit add basic migrations support in Postorius by following:
https://docs.djangoproject.com/en/1.8/topics/migrations/#adding-migrations-to-apps

Profile page: removed unused rows

Updated news file; version bump

removed unnecessary help text link

fix text-alignment of help text on settings pages

removed unused script files; added js-detection

Fix ErrorList import for django1.6 (Given by Aurélien Bompard)

Fix Django 1.6 compatibility

* Version bump. ...

* Updated news file.

updated news file.

Added subscription addresse switching (by Abhilash Raj). ...

Some modifications on summary view/html markup and wording.

* Added subscription moderation. ...

* Subscription attempts now show proper messages (subscribed/held for approval).
* Style changes on most forms.
* Removed some cruft from the forms module.
* Style changes on the summary page.
* Added list owner address to summary page.
* Added a note for moderators about non-advertised lists to the list index to avoid confusion.

rerecorded http test files

completed tests for list subscriptions: ...

- open list sub goes right through and adds a member.
    - moderated list sub is held for approval.

List subscription: Added proper feedback message, depending on immediate subscription or approval needed.

changed request identifier from request_id to token

renamed dev envs in tox.ini

rerecorded test files

added test for list subscriptions

local tox settings

Merging Ashish's code for convenient CSV export of the members list

Merge

Changed (and i18n'd) footnote on non-advertised mailing lists.

Fixed deprecated import

Merging Aurélien Bompard's most excellent one-character patch for unicode

Pep8 + Owner check

add pre_verified/pre_confirmed flags to subcription call if: ...

- user is logged in and subscribes to a list
- an admin mass subscribes a user

allow non-integer request ids in url

replaced legacy settings form

- form styles: larger text boxes ...

- new list identity and auto response forms