Make some change to the previous commit

Make some change to the previous commit

Here is a list of the changes:

* Enhance the call to plot in the constructor of SVG.Path, SVG.Line,
SVG.Polyline and SVG.Polygon

* Rewrite the description of the tests of the method plot for SVG.TextPath,
SVG.Path, SVG.Line, SVG.Polyline and SVG.Polygon to make it more precise

* Remove the useless parens surrounding track in the method array
of SVG.TextPath