Improve error messages for exceptions when rewinding

[Shimuuar]

Changes:

• Custom displayException is added to InternalError
• InconsistenceWhenRewinding stores offending hashes

InconsistenceWhenRewinding :: InternalError
  H of block that caused problem:
    Height 0
  Problem:
    Hash of calculated state doesn't match hash in block
  Expected hash (one that stored in block):
    Hash "swHmGH77tnTt3pc3sgCcgjakiyH"
  Hash of computed value:
    Hash "3GTLSwo2jMqQ8rSAkqoBVZ1poXg"