Marker styles are specified by the following properties:
A character indicating a plot marker to be place at each data point, or
"none", meaning no markers should be displayed.
The color of the edge around the marker, or
"auto", meaning that
the edge color is the same as the face color. See Colors.
The color of the marker, or
"none" to indicate that the marker
should not be filled. See Colors.
A number specifying the size of the marker. The default is 1. A value of 2 is twice as large as the default, etc.
colstyle function will parse a
and will return the color, line, and marker values that would result.
Parse the line specification style and return the line style, color, and markers given.
In the case of an error, the string msg will return the text of the error.