||Unarchives a LUA table which was archived into a plist using the NSKeyedArchiver.
- `archive` - the table containing the archive plist as a table
- `defrostFn` - (optional) a function which will be passed an object with a '$class' entry
- The unarchived plist table
- A 'defrost' function can be provided, which will be called whenever a table with a '$class'
- structure is present. It will receive the table and the classname and should either return a modified value
- if the class was handled, or `nil` if it was unable to handle the class. Eg: