Move require of select2 into spree_backend to make select2 available to extensions.
Fixing some text rendering issues that appear after updating FontAweesome

Fix select2 styles. Fix some button text rendering problems on OSX.

Fix table reorder handle align.

Fix .select2-choices background
Lockdown select2-rails temporarily.
Update select2-rails now that it has been fixed.
Put checkboxes before descriptions in shipping methods form

Fixes #3483
Fix IE8 compatibility issues with checkout.js and products.js

IE8 has a weird bug where function definitions outside of a ready statement were not being acknowledged