Turtle has a Shell #365
Description
In order for Turtle to be a useful Reptile, we'll want to make a Shell.
This should produce an HTML shell to take Turtle input and show turtle output.
Because Turtle is designed to be educational, this shell should be both fairly thin and as user friendly as possible.
The shell should be fairly customizable, and as easy to edit as possible.
It should include help and examples for Turtle, and make use of iconography where possible.