Added top-level module that calls path modules

I have added top-level module that calls all the sub-modules and is named based on the file name.  This makes it easier to import the entire set of paths into another OpenSCAD model.  I find that I usually want to import into another model and it was tedious to keep editing the OpenSCAD file generated by paths2openscad when something was updated in Inkscape.  To include in another OpenSCAD file, the following assumes that a filename of "cool_design5.scad" is used:

> use &lt;cool_design5&gt;;
>
> cool_design5(5);