Fixed syntax errors on account of non-assoc =.

Fix for a Define bug spotted by mjcg. When
dealing with recursive calls under a case,
if variables with certain names (those
starting with v) are bound in the case
pattern then it can happen that variables
generated during pattern matching can be
the same, leading to failed proofs. Totally
obscure, and dealt with properly (I think)
in normal pattern matching. So, a difference
between Pmatch and Functional. The fix is
to invent a class of variables not accepted
by the parser (i.e. starting *v) and to later eliminate
the weird names from any theorems coming out of Hol_defn.

Some other trivial mods made in passing also, plus
tests for the new behaviour.

Also a new conversional, MAP_THM, which applies the
given conversion to the assumptions and conclusion
of the given theorem.

Make this example run again.

These examples now build in Kan.0.

Ongoing faffing about.

Updates to handle change to type of Q.prove.

Added a cute introductory example from Laurent Thery.

Minor changes.

Initial revision