[CM] s7: Snd in CM, CM in Snd anyway - getting patterns.scm going

[anders.vinjar at bek.no]

Not disqualifying anything else in cm, but having cm/scm/patterns.scm in
snd would be a great start.

Running through patterns.scm now, it seems the main thing stopping it is
a void 'define-record.  Replacing these with calls on define-record-type
(srfi-17?) from snd/r7rs.scm makes it load and the test-patterns output
expected results.

Q: would it break things in CM if define-record got replaced with
define-record-type in pattern.scm?

To use it stand-alone, ie. in a running snd, it needs some things from
cm/scm/s7.scm + utilities.scm.  I guess for now its ok to just 'inline'
these dependencies, and aiming at a patterns.scm which to include with
snd only.

-anders