indexing: started moving rule indexing to kompile
moved indexing to kompile
indexing: added a comment
indexing: renamed class which holds the indexing table
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
indexing: added a TODO
indexing: removed an unused import
Merge pull request #271 from owolabileg/master

Moved Indexing to kompile
Java backend: cleaned up methods related to maintaining variables inside a term; added some javadoc
Java backend: moved KEqual:ite from MetaK to TermEquality because MetaK functions will not be evaluated during kompilation
Java backend: added an assertion to catch unevaluated ground functions
Java backend: fixed a bug related to unifying KLabelIndex and TokenIndex
Java backend: temporary hack to make #if#then#else#fi work for KList's
Java backend: changed the signature of the constructor of KItem because I need to get hold of the definition object when computing the sort
Java backend: more progress on computing the sort of a KItem based on user-defined sort predicate rules