Bugfixes and a new feature for anova.ppm to calculate adj. composite
lik. ratio.

   anova.ppm.R
   anova.ppm.Rd
      Added code for adjusted composite likelihood ratio test statistic

   plot.im.R
   spatstat-internal.Rd
      New internal function 'invokeColourmapRule'

   persp.im.R
      Now handles the case where 'colmap'
      is a function(range) -> colourmap

   persp.im.R
      Bug fix in new visibility calculation.

   DESCRIPTION
   NEWS
   updates.Rnw
     updated.