* operations/workshop/envelopes.h: removed unneded parameter from
compute envelopes.
* operations/workshop/c2g.c: (c2g): updated call to compute_envelopes.
* operations/workshop/stress.c: (stress): updated call to
compute_envelops.
* operations/workshop/max-envelope.c: added new op, that only outputs
the maximum envelope.
* operations/workshop/min-envelope.c: added new op, that only outputs
the minimum envelope.

svn path=/trunk/; revision=1463