2 V2_05_12   10/08/90  06.04.29

  +++ New Features:
  _________________

  New condition handler built in, that should catch floating underflows,
  overflows and divide by 0 everywhere.

  New command FUNCTION HOVERLAY to overlay a function as a histogram.
  FUNCTION PLOT and FUNCTION HISTOGRAM now always make a new plot.

  Register 102 contains the number of points summed over with a SUM command.

  2D Gaussian is now a built-in function (normalization must still be checked
  properly).

  Comments and Keys can now be associated by overlays which are on a different
  scale so that you can use their plot co-ordinates.

  +++ New Commands:
  _________________

  FUNCTION HOVERLAY         to overlay a function as a histogram
  FUNCTION ADD 2D GAUSSIAN  to add a 2D Gaussian

  +++ Bug fixes and General Improvements:
  _______________________________________

  Overlay when the plot had a different x scale use the new plot's scale.

  Dep dx... was wrong.

  Registers, parameters etc. now work properly as histgoram id's.

  Using errors on parameters is now OK again (TYPSCN bug),
  e.g. `FILL 1 r1 p2(3) r2 err2(3)'.

  Aborting plotting is improved, but still not perfect.

  You will no longer be asked if you want to keep commants and keys when
  reading commands from a file.

  Plot units now work properly in DRAW even when windowing.

  After a CLOSE, if you had captured a hadrcopy device, you are required
  to give a CAPTURE command.

  Improved handling of turning on/off ticks when overlaying on different
  scales.

  Improved r.m.s. calculation.

  +/- is replaced by correct symbol properly.

