cleanup like_any with some arel

Fixes #3701
Dont set preference on assets:precompile

Avoid opening a db connection when running assets:precompile to help
users to deploy their apps to heroku

Fixes #3703
Use alias_attribute, not alias_method, for CreditCard#cc_type

Related to #3704
Convert CreditCard#cc_type when it comes in from jquery.payment
Fix trailing whitespace
Fix error message to include all errors in Spree::Order instance

* When Spree::Order#next fails because an association is invalid, a
  red blank error message is displayed in the cart. This hides
  legitimate errors, like a bug I found in spreee_active_shipping.

Fixes #3714
Fix order_id assignment in OrderInventory

We missed the order param when creating inventory units through
shipments in OrderInventory. That will cause exception later on because
a InventoryUnit expect to always be associated with an order (which is
something I believe we should probably remove completely in the next
major release)

Fixes #3712
Remove blank username line in dummy database.yml mysql config

For some reason activerecord-jdbcmysql-adapter hates blank usernames
and will not connect despite the fact that mysql2 works fine. Removing
these lines doesn't break mysql2 so I see no reason to keep them there.
I'm trying to test my gems on jruby in anticipation of spree working on
jruby so this fix would be helpful. Here's sample Travis output showing
what goes wrong:
https://travis-ci.org/swrobel/spree_zero_stock_products/jobs/11136157

Fixes #3693