Add index view type support to the UI

[cbeer]

In a previous Blacklight release, we added support for different "view types" for a search result display (e.g. gallery, text listing, table, etc), but this was limited to back-end support for the feature.

Maybe it's time to add in some UI helpers, if a common pattern has emerged. Here's 3 examples:

[cbeer]

bump; now that we've got a Bootstrap 3 theme, are there any obvious places to put this widget? Maybe @ggeisler or @MrDys have ideas?

[MrDys]

I'm thinking something like this:

[MrDys]

(Though the class should be .active instead of .disabled on the first item...since it is the selected view.)

[cbeer]

Thanks @MrDys. I'll give it a go tomorrow.

[cbeer]