Bug #995

- Fixed bug #995, which mis-parsed UUIDs in filters as other elements (thanks
  to Bryce Harrington).
- Nibbler no longer permits 8-character UUID abbreviations, because too often
  they resemble other forms, such as '1111111d' which looks like a duration.
- Modified unit tests accordingly.

test/feature.891.t

@@ -157,7 +157,7 @@ like ($output, qr/one/, "Found with $short");
 
 ($short) = $uuid =~ /^(.{8})/;
 $output = qx{../src/task rc:bug.rc $short list};
-like ($output, qr/one/, "Found with $short");
+unlike ($output, qr/one/, "Not found with $short");
 
 ($short) = $uuid =~ /^(.{7})/;
 $output = qx{../src/task rc:bug.rc $short list};