This is Rx-diSpencer, a new version of Rx that dispences with
the complicated backtracking algorithm used in older versions 
of Rx and replaces it with another complicated backtracking
algorithm by Henry Spencer.

This is the first test release of the new algorithm, mostly with the
aim of finding out if everyone agrees that it implements Posix regexp
semantics.  This release has not been performance tuned and nothing is
yet known about how it does or can compare to other (non-Posix)
matching algorithms in "typical use".  It is known that the new
algorithm has a much lower formal complexity than the old Rx algorithm
for some important patterns.  All performance bets are off for
suitably nasty regexps involving backreferences, ^, and $ (which seems
to be inevitable).



