Merge branch 'master' of github.com:easydigitaldownloads/Easy-Digital-Downloads

# By Nikhil Vimal (9) and others
# Via Pippin Williamson (8) and others
* 'master' of github.com:easydigitaldownloads/Easy-Digital-Downloads: (26 commits)
  Removed 'choose_from_most_used' from category
  Fix some coupon insert hooks + prevent notices
  Add onChange event for CC validation #2801
  Make sure discount code exists before trying to apply it
  change default item count in [downloads] shortcode from 10 to 9 - #2785
  Remove backticks from CREATE TABLE SQL.
  Swap to use Scrutinizer for code coverage
  Update .travis.yml
  Update .travis.yml
  Update .scrutinizer.yml
  Scrutinizer for code coverage
  Changed $cart_order to $cart_index
  Extra arg to edd_complete_download_purchase filter
  Extra argument for price option amount filter
  Update readme.md
  Update readme.md
  Add GPL badge
  Fixing template docs for checkout_cart.php
  Template Documentation for checkout_cart.php
  Spacing for template docs in widget-cart.php
  ...