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