make polar plot
epolar ([xData,[yData,[legendText,[dash,[color[,width]]]]])
xData :
vector of alpha-data in rad
yData :
vector of radia-data
legendText :
text of legend, if empty string then no legend
dash :
0=solid line,>0=dash length,
<0=fill line,string=name of symbol
if a vector with size 1xn, then dash describes
a dash combination [space lineLength1 lineLength2 ...]
color :
color of plot, vetcor [r g b]
width :
width of plot