Add consistent Is* funcs for all PEGN Rune

[rwxrob]

Rather than have people know about the unicode package, and in order to create classes for stuff that doesn't have a unicode class, we need to add functions specifically for all the Class types in PEGN so they can be used without further annoyance. In fact, we want to keep really close one-one compatibility between rat/x and PEGN definitions so that they are completely interchangeable.