Changes by: Yegor N. Bryukhov (ybryukhov at gc.cuny.edu)
Date: 2005-11-17 21:48:18 -0800 (Thu, 17 Nov 2005)
Revision: 8194
Log message:

      1. Two minor optimizations for early detection of non-unifiable equations. Unfortunately, they do not help with the slow example in poplmark/naive.
      
      2. Added a counter (approximate) for recursive calls of path_checker - for debug purposes