xtc wish list:

* no-graphics mode (for quick & dirty Windows compilation)
* switch to toggle TAB/ENTER meanings?
* enrich messages slightly when entered with no parameters
* update documentation
- batch mode
- lgamma/gamma
- (docs: eq 5, \ missing before "partial")
* more features a la XPP:
 - ability to set/save 2D graph settings
 - multi-runs ("range" in Init settings)
 - data viewer (for space-time slices of some sort)
*  ability to "thin" 3-D graphs (esp surfaces) when viewing
* Warning for doing dumb things with PAR/CPAR
* Hitting letters in "3D graph" (instead of numbers) selects funny
   values
* grayscale (not stippled) color option
* direct PNG output of graphics window?
* file name on 2D graph header
* improved indicators in 2D window:
  - zero line
  - change "y", "x" to parameter/variable names
* (draw indicator line on 3D window?)
* toggle redraw mode?
