- added coor=2 option (for full citcom) to assign finer radial node
  spacing to top and lower layers of shell. The
  coor_refine=0.1,0.15,0.1,0.2 parameter specifies the radius fraction
  of the bottom layer [0], the fraction of the nodes in this layer
  [1], the top layer fraction [2], and the top layer node fraction
  [3]. I.e. the defaults will put 15% of all nz nodes into the 10%
  lower layer, 20% in the top 10% upper layer, and the rest in
  between.
  

- renamed gzipped output option ascii-gz

- built in restart facilities for temperature and tracers when using
  gzdir I/O


- added a composition viscosity function, CDEPV, based on two tracer
  flavors

  - for this to work, I had to move viscosity_input() *behind*
    tic_input() and tracer_input() in instructions


- added tracer_enriched option. If tracer = on and tracer_enriched =
  on, will reader Q0_enriched and vary the element heat production
  between Q0 for C = 0 and Q0_enriched for C = 1. I.e. this only works
  if C varies between 0 and 1.


- added an experimental option to write to a single VTK file (note
  caveats!) if ascii-gz is activated


  gzdir_vtkio = 2, will try to write VTK straight (experimental)

		  the VTK output is of the "legacy", serial type, and
		  requires that all processors see the same
		  filesystem. This will likely lead to a bottleneck
		  for larg CPU computations as each processor has to
		  wait til the previous is done.