Add option to format in edges visibility

An edges selector can now formatted into the end result
Add drawEdges function an toggleEdgesVisibility

These functions deal with the new g_comparisonPositons global variable,
in case there are comparisons, it draws them and responds to the
callback on whether or not to draw them with a selector.
Add script usage example for plot comparison

And added the option to reflect the addition in the footer.

Fixes #103
Add script usage example for plot comparison