Interim test release.

Hi all,

I'm pushing out untagged commit c7b4483840f371ffe5a531c46492e2cf9c4c6e1e.

I changed hash.c to use open addressing with linear probing instead of chaining. It seems to be working, but I'd like to circulate it.

There is also a new directive in the pattern language (something rare).

@(push) is a cousin of @(output). The output material is pushed back into the input, so it can then be matched. You can do useful things with this like reduce the number of cases through rewriting.

I'm not crazy about the name. Maybe @(pushback) would have been the better choice; it's not too late to change it.

Cheers ...