#274530 by yoroy, sdboyer: Changed legacy views icons in add content modal so they are immediately differentiable from view panes.

Superimposed 'L' onto the lower-right corner of each icon. We'll likely need to change this in the future when we refactor some of the naming schema, but it's quite adequate for now.

#260221 by sun, Pancho. Primarily codestyle cleanup; also fixed some missing leading slashes that were causing the edit icons not to appear in the new helptext for the display editor.

Protect panels legacy views from contexts that aren't arrays, even though they should always be an array.

Add legacy views; also add more administrative exposure to help the user learn where administration is.