Rewrite save/load code to be data-driven

[cathoderaydude]

Current approach to taking GUI input and saving/loading values is a mess. Everything should work like this:

ValidateForm() - Walks the entire UI, flags anything that's iffy (and returns false if so), otherwise copies values to backing variables

UpdateForm() - Copies all backing variables to UI fields

Save() - Runs ValidateForm(), pops a dialog if false to confirm if user wants to save last known good values despite invalid values in fields, then copies from backing variables to INI

Load() - Imports INI values to backing variables, then runs UpdateForm() and then ValidateForm() (just in case form rules have changed since last run)