isA for rRolonType checks

[William la Forge]

In AW4 we usually depended on the class name for type checking rolons, but that was not always possible--and then we used element type. But the problem with element type was that the type was often too specific and type inheritance was not supported.

In AW5, Rolons are not subclassed, but rolon type inheritance IS supported. Type checking for rolons then is done using the Rolon.isA(rolonType) method.

The isA method has now been implemented in the Kernel, and is working.

Bill