added prefilled username in Create a new list

Several changes: ...

* Fixed catching of AttributeError if API is not available
* Fixed resolving of current web host
* Removed hard-coded rest api urls from app code
* Fixed some typos, did some code clean up
* Consolidated various context processors into one
* Removed "Go to list"-Dropdown
* Settings.REST_SERVER now has to include the uri scheme name ('http://...')
* Settings.TEMPLATE_CONTEXT_PROCESSORS now only needs to include *one* processor for mailmanweb: 'mailman_django.context_processors.mailmanweb'

- Reorganized folder structure to make this a distributable project package. ...

- Added ez_setup.py and setup.py for automatic installation.
- Added README.rst