Merge identical states with different closures #14
Description
Right now, powersets are only merged when they contain the same set of NStates. This criterion is not sufficient to merge all redundant states, as can be seen here. Additionally, all DStates with identical transitions and accept values should be merged.
This needs to be done in a separate step after all DStates are resolved. Eliminating all redundancy will be computationally expensive, because we'd have to find all isomorphic subgraphs in the DFA state graph, which is an NP problem.