More fun with BETWEEN

I've nearly finished off the patch Christopher distributed.  Creates the
between node, and passes all regression tests except horology.  I need
to update outfuncs and readfuncs -- but hope to fix the below first.

Seems I have a funny case left (Note the last comparison should be
false):


regression=# select 3 between 2 and 4;?column? 
----------t
(1 row)

regression=# select 5 between 2 and 4;?column? 
----------f
(1 row)

regression=# select 1 between 2 and 4;?column? 
----------f
(1 row)

regression=# select 3 between 2 and 4 and 5 between 2 and 4;?column? 
----------f
(1 row)

regression=# select 3 between 2 and 4 and 3 between 2 and 4;?column? 
----------t
(1 row)

regression=# select 3 between 2 and 4 and 1 between 2 and 4;?column? 
----------t
(1 row)



The patch can be found at:
http://www.zort.ca/patches/postgresql_misc/between.patch

<a href="http://www.zort.ca/patches/postgresql_misc/between.patch">PATCH
HERE</a>