Create Histogram Module

[ccpandhare]

A module that displays the histogram of a given image.

This module could be a side chain module (One that doesn't really come in the sequence). What that means is, the "output" o this module would be equal to its input, so that more modules could be added on top of it, and histogram data would be an additional "output" instead.

We may use this NPM module too : https://www.npmjs.com/package/histogram

[jywarren]

This is done! #354