Filter river by channel

* River view filtered to display drops matching the selected channels.
Merge branch 'integration-dev' into rivers-ui-dev

Conflicts:
	themes/default/media/js/drops.js
Merge branch 'dashboard-content-dev' into integration-dev
Fix class names

* The exception classes were prefixed with "Swiftriver" instead of "SwiftRiver"
This was causing Kohana to throw an ErrorException on *nix systems
(case-sensitive)
Merge branch 'class-naming-fix' into integration-dev
Merge branch 'buckets-ui-dev' into integration-dev
UI: System messages in modals; In-button "loading" icon
Merge branch 'ui-dev' into integration-dev
UI: Revised River messages
UI: Improved collaborator role selection
Do not catch exceptions

* Catching the exceptions in SwiftRiver_API_Buckets prevents them
from propagating to the controller that initiated the request. Therefore,
when an error occurs, the user doesn't receive the appropriate visual
feedback
Merge branch 'integration-dev' into buckets-ui-dev

Conflicts:
	modules/SwiftRiver_API/classes/SwiftRiver/API/Exception.php
	modules/SwiftRiver_API/classes/SwiftRiver/API/Exception/Unknown.php