[CM] Snd 15.7

[Bill Schottstaedt]

Snd 15.7:

added CM_patterns.scm thanks to Rick and Anders

removed s7 ~<~> format directive
changed bytevector* to byte-vector* (r7rs.scm has definitions of the old forms)

checked: gtk 3.17.2|3, sbcl 1.2.12

Thanks!:  Tito Latini, Kjetil Matheussen, Anders Vinjar