Post-merge issues in VC mode #1: terminology fixes

[Eric S. Raymond]

I've spent the last several hours tackling the largest and (probably)
most difficult of the post-merge issues; the inconsistent terminology
resulting from the many layers of code conceptually harking back to
different VCSes.  Stefan was quite right to call this out as a
problem.

The code and manual now use the term 'revision' consistently for 
what we've been inconsistently calling a 'version' or 'revision', that
is a time slice from a version-controlled history.  

The terms 'current' and 'focus' are gone; the term used everywhere now
is the SVN-like 'working revision'. In particular, 'workfile-version'
is everywhere replaced by 'working-revision'.  This term is compatible
with changeset-oriented VCSes.

I think the manual is going to need more work to reflect the fact that
RCS-style x.y numbering is being superseded in newer VCs by integer 
changeset IDs.  I'll try to get to that this evening.

In general the VC portions of the manual need to be dragged into the
21st century; there is way too much focus on ancient VCSes and scant
coverage of more modern ones.  I'll see what I can do.
-- 
                <a href="http://www.catb.org/~esr/";>Eric S. Raymond</a>

As war and government prove, insanity is the most contagious of
diseases.       -- Edward Abbey