indexing: reverting previous changes to BottomIndex and TopIndex
indexing: added readResolve for singleton classes to avoid serialization problems
indexing: fixing latent bug in iterating over productions while creating the rule indexing table
indexing: making an interface type for different types of Rule Indexing mechanism
indexing: making it possible to specify which kind of rule indexing scheme to use during kompile
indexing: making path-index artifacts Serializable and cleaning out some unwanted files