Fix another harmless compiler warning in unixUnfetch().
Fix CREATE TABLE ... AS so that it works with column names that are empty
strings.
Allow a VALUES clause to be used any place that a SELECT statement can be
used.
Remove unused structure definition from parse.y.
Do not use sprintf(), strcpy() or strcat() in the implementation of the
lemon parser generator tool, to avoid compiler warnings in OpenBSD.
In LEMON, fix a bug in the text formatter introduced by the previous
commit.  Also add the new "%token_class" directive for defining symbolic
names that stand any one of a collection of tokens.
Add the "%token_class" directive to the LEMON parser generator.  This opens up
the possibility of simplifying the parser.  Also remove all calls to 
sprintf(), strcpy(), and strcat() from LEMON to avoid compiler warnings
on OpenBSD.  (Aside:  It is this change to avoid harmless compiler warnings
that was the cause of the reason spat of bugs.)
Optimizations to the SQL language grammar that result in a small size
reduction and speed increase.