kill the abbreviated tags feature

[Bill Trost <trost@cloud.rain.com>]

Gary Capell writes:
    d9509072008 selecting bits of relative tag works (*)
    
    *  getexpand checks to see if the selection is at the start of
    a pane_tag and doesn't start with a slash....

Ugh, this is getting worse all the time, and it's still a feature that
causes me grief.  In the process of moving the smooth-scrolling code
into a newer wily, I had to flip back and forth between wily versions.
I quickly got to the point where I couldn't tell which version of the
code I was looking at because all I had was a file name and no
directory name.

There are two solutions to this problem that seem "obvious" to me:

 1) Fix the real problem: There isn't enough room in tags.  Figure out
    how to give tags more room, or how to require less space of them,
    *without* destroying the principal bit of information (as opposed
    to stuff that's useful but tells you nothing) in the tag -- what
    it is you're working on.

 2) Use environment variables as prefixes.  Using "$home" instead of
    "/ogi/students/trost" would save a great deal of space.  Let the
    user specify other variables that could be used in a similar
    fashion, and pick the largest one when filling a tag.

 3) Make tags scroll horizontally.  Scary stuff.

I'd be happy with the second one, and I'd be happy with ignoring the
problem completely.  But I really want to be able to tell at a glance
what it is I'm editing.