added back delay_st_c
bad dsp sig
bug fixes for closure-in-first-position check
*very* experimental support for SMP audio

This has only been tested on OSX to date.
*should* run everywhere but untried and
definitely unoptimised.

dsp:set! now also the following parallel option

(dsp:set! dspsum dsp1 dsp2 dsp3 ...)

where dspsum must have the signature
[double,double*,double,double,double*]

and dsp1,2 etc.. have the 'normal' signature
[double,double,double,double,double*]

dspsum takes as its first argument a pointer
to an array of input data coming from 'n' number
of dsp functions (as defined by the number of dsp
closures provided to dsp:set!).
Merge branch 'master' of github.com:digego/extempore

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