Specify class name for calculator association in calculated_adjustment

Otherwise, top-level classes that include this module will have an association that looks for ::Calculator, rather than Spree::Calculator
Override default jQuery UI styling for Spree auto-complete results.

Fixes #3103
Disable Jirafe
Remove dash gem
Remove overview tab until Jirafe issues are sorted.
Remove dash from rake stuff
Promos using CreateLineItem action should check eligiblity before performing

Fixes #3147
Allow admin-created orders to accept payments

Looks like an invalid state check for the order was hanging around
from long ago.

[Fixes #3098]
Merge remote-tracking branch 'upstream/1-2-stable' into 1-2-stable