[CM] Snd 15.3

[Bill Schottstaedt]

Snd 15.3

s7 procedure-documentation no longer refers to an optional string that happens
  to be the first thing in a procedure body, but to the value of a variable
  named 'documentation' in the procedure's environment.

procedure-arity is deprecated, s7_procedure_arity replaced by s7_arity.
  procedure-name is deprecated. data-format removed (see snd15.scm).

format has another control directive: ~N or ~n which gets a numeric argument
  from the argument list: (format #f "~nD" 20 123)

with-sound argument order changed slightly. It is now: output channels srate.
  Ideally, other Snd functions like new-sound would follow the same argument
  order -- let me know if this change would cause you problems.

float-vector-equal? -- relative difference of two float-vectors.

make-iterator, iterate, iterator? -- replace make-hash-table-iterator and 
  hash-table-iterator? These are generic functions to traverse sequences.

if (*s7* 'safety) > 1, optimization is turned off
(*s7* 'maximum-stack-size) is now (*s7* 'max-stack-size)
(*s7* 'print-length) replaces *vector-print-length*
(*s7* 'bignum-precision) replaces *bignum-precision*
(*s7* 'stacktrace-defaults) replaces *stacktrace*

checked: sbcl 1.2.7, gtk 3.15.4