Add logic to plot the found path and show the start and the end

[fif911]

Here is a small update I find to be useful for people who want to test their algorithms.

[fif911]

This is the result of the function call.

[john-science]

I have two thoughts on this PR:

1. The goal of "Example 2" was to show people the fewest possible lines of Python code needed to plot the thing maze. So this new example is not as good from that respect.
2. Perhaps you can make this a new example between the current "Example 2" and "Example 3" that shows this better copy/paste display example. That seems more useful for the users, as long as it is clearly described as such.
3. You made a change to the code, but didn't copy/paste the new image into the docs. (So, in your PR the code doesn't match the image below it.)

Does that make sense? Thoughts?