Add a "template" functionality for all methods

[willu47]

Add a "template" functionality for all methods, to put parameter samples into a model input file (like lots of older Fortran/C++ models have). Here is an example: https://gist.github.com/jdherman/fe0b81100ee83e1f6532. If you had 1000 samples, this would create 1000 copies of the model input file, with the variable names substituted with values.