Proposal for a new plotting feature

[Sayandip Halder]

Polygons and triangles cannot be plotted directly by any plotting function. Sympy can have a new plotting function for polygons which can plot these structures directly and the user does not have to write a separate loop.

The proposed function will work something like this

>>> p = RegularPolygon(Point(0,0), 1, 5)

>>> plot_polygon(p)

Let me know what do you think!