Address flake8 complaints
Refactor settings.js templating to support root pages

The previous settings.js templating assumed that the URL always contained
an instance ID. Now that we are starting to add 'top-level' pages (e.g.
user page) we need a settings.js template that works without an
instance.

As part of this change I fixed script src urls with double slashes and
added a simple context processor to make the SITE_ROOT setting from
settings.py available to all templates.

I changed mimetypes from application/x-javascript to the now standard
application/javascript (reference: http://stackoverflow.com/a/9664327)
Add space to mollify flake8
Merge branch 'ecobenefits-server-template'
Merge branch 'master' of https://github.com/azavea/OTM2

Conflicts:
	opentreemap/treemap/tests/views.py
Merge pull request #101 from jwalgran/topic/root-config-js

Refactor settings.js templating to support root pages