startapp options
Vectors for the future
introduce option picking logic
Option selection working

There are a lot of rough edges in frontend and some
in backend, but main selection functionality is implemented.

TODO:
* quote view (quantity(unit and discrete), custom size support)
* selection validation(both in frontend(required fields) and
backend (choice conflicts))
* OptionChoice refactor, move to options app
* Price, pick_price updates
Display proper captions in fields
Choice validation and error reporting
Move styling to css file and cleanup a bit
better data type handling in form
better data type handling (in template)
Transfer OptionChoice class to options app
More convenient OptionChoice ordering
Show missing thumbnail image for OptionChoice if none defined

Define MISSING_OPTIONCHOICE_THUMB_URL in settings
Better session data handling

Reset saved choices (in session) when opening different product.
Price calculation working (but incomplete)
point button to new options picker
Merge branch 'master' into options

Conflicts:
	gap/geniusautoparts/urls.py
Merge branch 'master' into options
Avoid conflicts of finish button and form elements with name 'finish'
Correct price calculation for prices with quantity != 1 per price
Proper sorting and more clarity in picker descriptions