allow syberia stages to be built using arity 1 functions
Allow par instead of opt as well for options arguments
this also means we no longer need modelenv for model_stage
convert some more functions to arity 1
convert some more functions to arity 1s
I forgot about default arguments...stages should be able ot have any arity
Merge pull request #11 from robertzk/stage_arity

allow syberia stages to be built using arity 1 functions