BUG: Patch rank() uint64 behavior

Adds uint64 ranking functions to algos.pyx to allow for proper ranking with uint64. Also introduces partial patch for factorize() by adding uint64 hashtables and vectors for usage. However, this patch is only partial because the larger bug of non-support for uint64 in Index has not been fixed. Also patches bug in UInt64HashTable that had an erroneous null condition that was caught during testing and was hence removed.

Author: gfyoung