New stuff related to fonts, titles, colours etc.

   util.R
      another tweak to fontify()

   plot.plotppm.R
   plot.plotppm.Rd
      New argument 'pppargs'

   measures.R
      Bug fixes in plot.msr:
       did not plot the legend for the atoms.
       mangled the title.

   plot.owin.R
       Tweaked allocation of space for title.

   colourtools.R
      to.grey now handles the case where x is a function(n)

   tests/colour.R [New file]
      Added tests of col=function(n){ ..}

   NEWS
     updated.