Allow specifying distributions for variables in lieu of or in combination with default values.
Fallback behavior should be to randomly draw from a distribution if running a simulation with no default values specified. Eventually exploit this information to modify lowering step when targeting Gen.jl
Splitting out from #16
Allow specifying distributions for variables in lieu of or in combination with default values.
Fallback behavior should be to randomly draw from a distribution if running a simulation with no default values specified. Eventually exploit this information to modify lowering step when targeting Gen.jl