fixed slicing of map of parameters
Merge branch 'model_as_dict'
a bug in checking parameter id_name and clearing up error value
Merge branch 'model_as_dict'
leave variance as 1 if not explicitly set, moved chisq calculations to after storing fitting parameters
improved passing of active values when copying only a selected index of model
Merge branch 'chi_squared'
Merge branch 'model_as_dict'