Fix access_fn in Dashbiard navigation
Update oscar/apps/dashboard/nav.py
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
Split up contributing guidelines

They were getting quite long. They've been split up in several
subsections. Some of them are borrowing heavily from the Django docs.
Docs: Merged content from old docs

my_model_customisations_arent_picked_up now lives in a subsection of the
recipe how_to_customise_models.

The old conventions.rst is now merged into the new coding-style.rst.

The old search.rst has been dropped as it seems outdated.
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
Docs: Centralise sandbox instructions

Building the sandbox was explained in multiple locations, and in
slightly different ways. The sandbox now has a separate document.
Docs: Add debugging trick for model customisations

Was posted on the mailing list.
Docs: Added documentation for tox tests
Docs: Merge tests/README.rst into docs structure
Docs: Move design decisions and dev environment

They really don't belong in /contributing.
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.
Add new `render_product` templatetag

This looks for an overriding template for the product partial, based on
the product's UPC and product class.  This hook allows projects to
provide custom partials for changing how a product appears in browsing
views.
render_product: Docs & default paths