Clean up some minor issue with JSON
Moving PROMOTION_POSITIONS to defaults.py, allowing customization.

Now I can define new blocks under settings.py, without needing to overwrite an application.
Added doc about OSCAR_PROMOTION_POSITIONS setting

Also grouped promotion settings together.
Add defaults to the counts on the product summary dashboard page
Merged ProductUpdateView and ProductCreateView

There's a lot of code duplication between the two. This is an attempt of
merging the two.

* The additional formsets are now easily overriden.
* is_valid logic is more concise
* is_stockrecord_submitted is now more robust
* Fix: Partner and Partner SKU were optional. They're required, only the
  entire form is optional.
* Fix: StockRecordForm errors are now displayed
* StockRecord is now deleted when clearing all fields
Merge pull request #548 from tangentlabs/experimental/mergeproductviews

Merge ProductUpdateView and ProductCreateView
Merge pull request #598 from tangentlabs/davividal-promotions_positions

Made position of promotion blocks customisable
Merge pull request #541 from tangentlabs/fix/cleanup_json_serialisation

Renamed variable shadowing builtin
Prevented selecting itself as parent product

It was possible to select the product itself as parent product. The
ProductForm __init__ function now excludes the instance from the
parent-field queryset.

Fixes #586.
Remove obsolete 'form-actions' section from underneath the page edit form
Merge pull request #603 from zoyalab/pages-dashboard-fix

Removed obsolete 'form-actions' section from the page edit form
Remove django from requirements.txt

This was causing tox to choke as there were conflicting requirements
(well, kind of).  Removing it allows tox to run normally but means we
can't run 'upgrade' without conflict.

I've adjusted the makefile to use install for the 'ci' target now
instead of upgrade.

Fixes #600
Merge branch 'master' into releases/0.5