ParameterCollection and supporting classes requre extension and updates

Additional parameter types

• File and Folder selection
• selection from the set of options (list parameter)
  • should options be strings or any arbitrary type?
• array parameter?

XML reader and writer for ParameterCollection

GUI support:

• auto-generate GUI panel element for each ParameterCollection item
• make a function getParameterPanelCollection
• ?make some parameters invisible in GUI by defining GUI visibility tag for each parameter

Create usage examples