Updated setup_top_menu.js 

added color customization

The coders are able to set the tracer’s colors to anything they want!
Since I use the style background color attribute on the div it can
accept a wide variety of values for the background color.

I first wanted to pass in some color value when calling notify or
select but then I realized there is a lot of issues with the amount of
parameters . So I thought of doing some sort of global set like the
HTML canvas/context does.

Tracer now has 5 new methods for setting the colors.
_Set(name)FillColor(color_goes_here).

The logic of the setting fillColor and it being displayed should be
similar to the canvas/context fillStyle setting. It will keep using
that color until the color is switched again.

I had to change the clear method inside array2d.js also to handle the
new coloring change.

Longest common subsequence

Correct spelling of sieve_of_eratosthenes directory

Correct another misspelling of Eratosthenes

Correct one more misspelling of Eratosthenes

Correct misspellings of Sieve of Eratosthenes

Move npm script

removed explicit Promise declaration from gulpfile

Added Maze creation example