Adds avatar to collab listing on custom collection

Collaborators listed on custom collection in the "collaborators" tab
have their avatar shown next to their name. Updates CarrierWave to most
recent version so we don't have to specify mime types. Moves credits
info under Article tab instead of appearing under every tab.
Merge branch 'development' into custom_collections_301_rb

Conflicts:
	Gemfile.lock
	app/views/custom_collections/show.html.erb
	config/routes.rb

Fixes breakage due to upgrading rspec from 2.14.1 to 3.0.

Adds views for CustomCollectionItem which were only on my machine.

Adds routing specs for videos and programs.
Merge pull request #372 from afred/custom_collections_301_RB

Adds avatar to collab listing on custom collection