Include sample in top level rake test and test_app
restrict cost_price to admin users through the api
add uniqueness validation in spree preference
Avoid browser default font on backend icons

In the Spree backend UI, icons are used by adding classes to existing elements, without adding something like `<i class="icon-something"></i>`.
But font-awesome-rails sets the font-family to just `FontAwesome`, which results in the browser default font-family (usually, Times New Roman) being used for any text that appears next to an icon (on Firefox, at least).
Screenshot: http://adobe.ly/1mb9oOH

Fixes #4885
Capture on dispatch. Fixes #4727
Add changelog entry for capture on dispatch.
Validate uniqueness of variants sku. Fixes #5015
Initial work on how to extend spree to support extensions that customize line items.

Adds the build_options hook for extensions to process their own cart params.

Fixes #4546
Address feedback and fix specs. refs #4546
Fix analytics check to run only when there is an order. Fixes #4929
Fix duplicate sku in samples.
Order history should be reverse chronological. Fixes #5024
return 204 for PUT /orders/empty
Fix spec for ruby 2.0

With Ruby 2.0.0 p451 this was giving:

    expected: 95.17
         got: #<BigDecimal: 95.17000000000001>
Add roadmap url. Fixes #5025
Merge pull request #5032 from HoyaBoya/fix/empty_order_204_response

return 204 for PUT /orders/empty
allow specifying Kaminari page_method_name

only define custom page method if page_method_name != page to avoid recursion
Fixes #5035
Use the proper flash

This is not a success
Fixes #5034
Update Google Analytics

Updates GA tracking code to support Display Advertising. See: https://support.google.com/analytics/answer/2444872 for more.
Fixes #5030
Fix order merging. Fixes #5028