Uppity can only go up once

[t-bone]

1. Navigate to  http://www.example.com/a/b/c
2. Go up, via clicking the toolbar button or pressing Alt-Up
3. Repeat

Step three will fail. If you go up once, such that the "selected" item in the drop down is not the first, you'll always go to the second item in the list.

In fact, if you start from that URL, and navigate to  http://www.example.com/a/ then you will still return to the second item (/a/b/), and not go up where you expect.

[t-bone]

(In [516]) Fixes #275, Refs #236

• Bump version number.
• Throughout the entire system, more carefully consider which is the "current" and which is the "next" URL, if any. This changed as of #236 to be more complex.