[to 20201110]

- make a site for community uploaded data

- make separate directories for default and optional data files

- diagram(): make error or warning for NA values of affinity

- move protein.equil() example (previously in equilibrium.Rnw) to JMDplots.

- move extdata/bison to JMDplots package.

- add elements from RH95.

- add check to mosaic() that 'stable' values have the right dimensions.

- anintro.Rmd, help files: make it clear that species with
different units (cal, J) in OBIGT can be used in subcrt, diagrams, etc.
in CHNOSZ.

- move H2O92D.f and R wrapper to a separate package (so people
don't have to compile anything to install CHNOSZ updates).

- add empty diagram -> exceed.Ttr hint to anintro.Rmd.

- replace CoCl2-4 example in anintro.Rmd with different species
(CoCl2-4 has been added to OBIGT).
