Changing OSCAR_PRODUCTS_PAGINATE_BY to OSCAR_PRODUCTS_PER_PAGE
Moving PROMOTION_POSITIONS to defaults.py, allowing customization.

Now I can define new blocks under settings.py, without needing to overwrite an application.
Adding doc about the configuration option
Adding doc about the configuration option
Adding docs about how to setup flatpages.
Merge branch 'pagination' into merging
Merge branch 'flatpages' into merging
Merge branch 'promotions_positions' into merging

Conflicts:
	oscar/apps/promotions/conf.py