Add a ClassChecker cache

When overriding rules and/or interface rules are installed it is necessary to traverse the super chain and/or implemented interface tree for a given class X at load time, This is needed in order to detect whether a rule referencing a super or implemented interface of X needs to be injected into X.

The class traversal must proceed by loading and checking the bytecode for supers and implemented interfaces as a byte[]. A cache retaining ClassChecker instances derived from previously loaded byte[] instances may be helpful in avoiding the cost of repeated loads.