[PATCH 0 of 3 RFC] ui.configpath() tweaks

[Greg Ward]

Following up in this thread:

  http://thread.gmane.org/gmane.comp.version-control.mercurial.devel/44823

Patch #1 is what I proposed and Matt endorsed.

Patch #2 puts it into action in extensions ... except for acl,
whose test seems to enforce the wrong semantics (relative
to current dir). I know nothing about acl and I'm reluctant 
to change it this late in feature freeze.

Patch #3 is going even farther out on that limb.

Greg