Lighten greys to match mockup. Standardize hover color across various tables and menus. Factor up colors as much as possible so we don't destandardize accidentally. Ref bug 959863.

I intend that whitening the Switch Tree menu and the odd rows of the folder-contents table will provide a bar of white to delimit the search panel from what comes below. But I think we need to increase the left margin of what's below to make that work. We'll see if it works out.
Give the Filters menu a hover highlight. Ref bug 959863.
Use fewer different font sizes. Ref bug 959863.

Set base font size to the one we most often use, and consequently remove a lot of font-size adjustments.

Remove styling of unused "top" class.
Improve look of search results. Ref bug 959863.

* Keep icons in search results from clipping.
* Right-align line numbers.
* Add some space between the icons and the file paths.
Increase horizontal padding of content area. Ref bug 959863.

This separates it from the search panel and helps less ambiguously group the breadcrumbs with the lower part of the page.
Shrink and remove icon from Switch Tree menu. Ref bug 959863.

This makes it close to the height of the breadcrumbs, which it's supposed to visually pair with. It also draws the eye less; there's no reason we need to especially call people's attention to it.

Also, move the down-arrow so it's more like the Filters menu's.