Horizon messages (toasts/growls/alerts) now inherit from a theme.
In addition, a default message type was added 'default', since it
it possible to kick up an alert without a type specified at all.
To test all the types, run the following command on a JavaScript
console with Horizon loaded:
horizon.alert('warning', 'foo');
horizon.alert('info', 'foo');
horizon.alert('success', 'foo');
horizon.alert('', 'foo');
horizon.alert('danger', 'foo');
Partially-Implements: blueprint horizon-theme-css-reorg
Partially-Implements: blueprint bootstrap-html-standards
Change-Id: Ice65773fe1d2cdc0305fd01acd8bea3d3f84a9fa
c7de6d5bee