update blah blah;
added a trivial test case;
moved some stuff from peano to common, because it's getting used by other stuff;
this also fixes what I thought was a bug, earlier;
this was merged into common.scheme, since (equal? ...) needs it - the file remains because the test cases need to live somewhere;
oops, I meant to include this in the previous commit;
oops, I meant to include this in the previous commit;
this was merged into common a while ago;
a few more simple test cases;