display descriptions with ellipses

[devoncarew]

• fix Provide a hint where text is hidden behind a link in the overview #808; display one line of a description summary - use ellipses if it doesn't fit. This had been our behavior; not sure if this regressed or it was a conscious choice to move away from it.
• display the glass pane w/ slightly less opacity
• the columns on the index page now add up to 12
• move the nav from right to left on the index page. This way the libraries nav is in a consistent place when it's visible on the page.

[devoncarew]

fix #806

[sethladd]

Thanks!

move the nav from right to left on the index page.

I don't care if that particular nav is on the left or right, but I'd like it consistent across all the pages. Can we move all the other pages, too?

[devoncarew]

The library nav is on the left for all the pages.

page	left nav	right nav
index	libraries	none
library	libraries	library members
class	library members	class members
class member	class members	none

[devoncarew]

I think this is the least surprising structure for users. The first and last pages (tree root and leaf nodes) are a bit of special cases.

[sethladd]

Bonus points for using a table! :)

I find it inconsistent, but the world is a messy place.

lgtm!