Improvements to Metropolis-Hastings algorithm for hardcore models.

   straush.c
      Minor tweaks while debugging.

   rmhmodel.R
      Table of model specifications now includes 'hardcore' function
      (but this is not currently used.)

   methas.c
   mhloop.c
      Metropolis-Hastings algorithm now includes a pre-processing
      stage in which illegal points (cif=0) are immediately deleted.

   NEWS
   DESCRIPTION
    updated.
    Temporary version number: 1.39-1.027