Add failing specs for #2306.

Add a renamed resource before adding the original resource and asserting
that both are present in the ResourceCollection.
move a few hard coded colors into variables
ResourceCollection#add to act on @resources directly

Using `ResourceCollection#[]` to check for existing resources could
potentially return an incorrect resource and it would wrongly determine
a resource was already in the collection. This change will ensure a resource
added is only considered present if its `resource.resource_name` object
is an exact match in the internal `@resources` hash.

Fixes #2306.
More specs for ResourceCollection#[]
Merge pull request #2456 from zorab47/resource-registration-lookup-fix

ResourceCollection#add to act on internal @resources directly
Merge pull request #2454 from ilyakatz/refactor_hard_coded_colors

move a few hard coded colors into variables
Revise formatting of form documentation to better link to Formtastic
run pimpmychangelog
update Rails 3.0 precompiled JS
update changelog
fix code display in changelog
Add section about on_unauthorized_access option for use with CanCan
Fixed Issue number

`redirect_to :back` won't work if there's no referer, so I don't think it's a good example to give.
Merge pull request #2462 from monfresh/patch-1

Add documentation about on_unauthorized_access option for use with CanCan
Add form semantic_errors usage to documentation

Document the semantic_errors ability added in Pull request #905

https://github.com/gregbell/active_admin/pull/905
remove extra line
Added Gittip badge to the README
get gittip badge linking properly
Updated czech locale
Merge pull request #2472 from romansklenar/patch-2

Updated czech translation