The model-free constraint matrix A is now of numpy.int8 type.
The values of this matrix should be negative, zero, or positive integers for model-free analyses,
so the type has been changed. When using the example at
https://mail.gna.org/public/relax-users/2012-03/msg00037.html (Message-id:
<CAED9pY_Z1wGEg3gZo3WCkhvYTBdqs-Feex5Og4vJFovgJkUOyw@...>), the virtual memory usage
during Monte Carlo simulations drops from 648 to 641 Mb. This should also increase the scaling
efficiency on clusters.
