Inheritance and PreferencesRule fixes, commands added

 - Changed inheritance prioritization to an automatic `2` that way they can still be overridden
 - Changed field name `Inheritee` to `Inheritance` cus it looks nicer
 - Initialized `Inheritance` to `null`
 - Moved material matching code to a method `Utils.MatchMaterial()`
 - Added single-material rules in the `PreferencesRule.MatchesMaterial()` function
 - Added an additional `*` matching rule in `PreferenceRule`
 - Added commands:
 - - `sortinghelp`
 - - `sorting view-classes`