WISHLIST

o check out the following in case there is something useful for us:
	http://alphatcl.sourceforge.net/wikit/182

o ensure examples work at https://yacas.readthedocs.org/en/latest/tutorial/index.html

o some 'syntax mapping' yet to be done, e.g.  atan2

o debug the S4 interface

o provide a yacas dll to R so R/Ryacas and yacas both run in same process

o implement OpenMath interface in R to yacas direction

o create a symbolic matrix class?

o consolidate/improve vignettes

o interface to a second CAS -- which ones support OpenMath?

o check whether this works in yacas 1.0.62
Solve({mean==(A/(A+B)),variance==((A*B)/(((A+B)^2) * (A+B+1)))}, {A,B})

o improved yacmode:
  -- allow uparrow
  -- tcl-based?
  -- based on Soren's mini commander?

o add remaining yacas commands to Sym interface

o add remaining yacas commands to Expr interface
