Fixed #14 -- Allow customizing the redirect query param name

Allow a page to invoke a login followed by a redirect to the given page. This
mirrors the functionality of the default login view.

It also brings over the login view's `redirect_field_name` parameter,
allowing a site to customize what query parameter to use. This helps
when transitioning older codebases to the new view.

The template by default uses "next", but this can be overridden in
custom templates.

This adds unit tests covering a custom redirect URL using the standard
`?next=` query parameter and a custom query parameter defined by
`redirect_field_name`.

Thanks to Christian Hammond for the patch.
Moved token instructions to template

Thanks to Christian Hammond for the suggestion.
Speed up backup token generating
Mask more digits of the phone number
Released 0.2.1
Next release will be at least Alpha
Fixed #13 -- Allow Twilio language customization

en-gb is now included as example customization.
Released 0.2.2
Release notes
Added django-user-sessions to example app
Added test instructions
Added all supported Python trove classifiers
Pulled two new languages: Hebrew and Arabic

Thanks to KuwaiNET and Kunda for their effort.
Warn early when translators provide invalid twilio language
Preliminary right-to-left support in example app

The boostrap theme doesn't support rtl, so this means that the
navbar doesn't get flipped over. Other elements appear to be
alligned rtl.
Typo

Thanks to Kunda for reporting the issue
Updated languages from transifex
Fixed test that failed for fixed typo
Pulled languages from Transifex
Fixed #16 -- Django 1.4.2 or higher is required

Django 1.4.2 introduced the six compatibility framework, which
is used by this app.