Display directory storage indexes in directory listings

[kpreid]

In the WUI, the only identifier of a directory when you are viewing is its storage index. This identifier is not displayed when you are viewing a directory containing it. I propose that the storage index of a directory be displayed (deemphasized) whenever it is listed in another directory, so that it is easier to correlate different views than click-and-see-where-the-link-goes or visually comparing URLs.

Furthermore, if #1178 is done, then the storage index may also/instead be used as an icon for the directory (perhaps with the addition of icons for files, for consistency.)