Use a PyPI version of Haystack

This requires a more recent version of Whoosh for the sandbox too.
Minor search tweaks

The start of a final push to get search ready for 0.6.
Remove import_module
Remove suggestions view from search app

This will return in a stronger form for v0.7.
Adjust demo shipping methods for 0.6
Update demo checkout for 0.6

Fix issue with submit() method and a few other small issues.

Fixes #913
Merge pull request #939 from schoonc/fixduplicatefield

Remove duplicate "Date joined" field
Merge pull request #638

Conflicts:
	oscar/apps/dashboard/catalogue/views.py
	oscar/apps/dashboard/partners/views.py
	oscar/apps/dashboard/reviews/views.py
	oscar/templates/oscar/dashboard/catalogue/product_list.html
	oscar/templates/oscar/dashboard/orders/order_list.html
	oscar/templates/oscar/dashboard/pages/index.html
	oscar/templates/oscar/dashboard/ranges/range_list.html
	oscar/templates/oscar/dashboard/reports/partials/open_basket_report.html
	oscar/templates/oscar/dashboard/reports/partials/order_report.html
	oscar/templates/oscar/dashboard/reports/partials/submitted_basket_report.html
	oscar/templates/oscar/dashboard/reports/partials/user_report.html
Merge branch 'master' of github.com:tangentlabs/django-oscar
Filter by date range in Dasboard/Reporting, if provided
Enable Multi-Image content block

Display multi-image block using bxSlider.
Extend offers to work when taxes aren't known

This involves some quite involved changes to the internals of how offers
and organised.  A new boolean field has been added to the offer model to
indicate whether to apply to prices exclusive of tax.  This is used
within the offer methods to determine whether a basket meets a
condition, and how to apply the benefit if it does.

Fixes #925
Fixes #924
Rename basket Line properties for clarity

Previous names were ambiguous as to whether discounts were being
included or excluded.
Replace wysihtml5 with TinyMCE editor 4.0.10

bootstrap-wysihtml5 was too buggy.  I was trying to avoid TinyMCE but it ended up
being the easier to use.  I tried with CKEditor but it proved too
difficult to configure.

Fixes #757
Fixes #946
Fixes #945
Fixes #944
Fix several issues for Django 1.6
Adjust version dependencies for Django 1.6
Disable template timings toolbar panel
Add migration for NullBoolean field
Extend help text for promotion models
Add more links to promotions dashboard templates