YSCALE=<min.value>,<2nd value>,...,<max.value>
(in PLOT operation for diagrams and curves) determines a linear scale
and the scale notations on the Y axis.
The texts (numerical values) on the Y scale are set aligned to the right
by default.
To override this practice, a specification YSCALEPOS=y1,y2 can be given.
y1 is a number giving the relative start position of the texts for YSCALE
and y2 similarly for YSCALE2.
Otherwise the rules of YSCALE are same as those of XSCALE.
X = Information on XSCALE
P = General information on plotting