Fix the select_related() call in Basket.all_lines()

product__stockrecord doesn't exist anymore, use the stockrecord on the
basket line
Rename partner.utils to partner.importers, and comments

It only contains importers. Also added comments about their usage,
or lack thereof.
Don't init select2/wysiwyg widgets outside of el

This wasn't done previously because I didn't know how.
Init invisible widgets as well.

To prevent initialization use class no-widget-init on the element itself or any parent element.

Fixes #1210.
Raw HTML textarea shouldn't be wysiwyg'd

Fixes #1211.
Move demo site importer and commands into Partner app

That way, they aren't left to rot in the bigbang app. Gives us one
central place to refactor them.

Fixes #1238
Remove demo.bigbang app

It's empty now, so can safely be removed.
Universal newline mode for CSVUnicodeReader

Some demo site fixtures have Windows line endings, and this fixes it.
Universal newline mode is the default for Python 3 anyway, so it makes
good sense.
Merge pull request #1243 from mbertheau/fix-widget-initialization

Fix JS widget initialization
Update release notes to include changes of #1243
Merge pull request #1241 from mvantellingen/update-basket-all_lines

Fix the select_related() call in Basket.all_lines()
Make access check function for dashboard easier to customise

* It can now be specified in OSCAR_DASHBOARD_DEFAULT_ACCESS_FUNCTION
* nav.py and menu.py were split up so that Node can be dynamically
  loaded and hence overridden

I recently needed to alter the access function and realised it's not as
easy as I thought.
Move the dashboard product list to django-tables2
Keep current tab and ordering when returning to the list after editing
Move table caption into <table><caption>

This gives better semantics and it's consistent with the users dashboard
Move dashboard categories list to django-tables2