Calculate a lookupcode to avoid multiple calls to BitSet.hashCode()
Fixed issue in Memoization put methods that inserted wrong key-value pairs.
BitSet hashing is incredibly slow. This commit introduces a workaround for this in the Memoization cache where we see this creating an issue.
Introduced BitSetFastHash class to work around slow BitSet hashing.
Merge pull request #232 from heiseda/master

BitSet.hashCode Work around