Styling and Draggable weight components

This PR makes some changes to style in test.js and view.js.  Additionally, it introduces new logic in weightView.js which allows for users to interact and control the perceptron's weight vector.

After clicking 'Go', a new button, 'Stop' can be pressed to end the automatic iterations prematurely.  When the perceptron is not running, numeric labels under the graph are displayed to the user, showing the perceptron's current internal weight vector.  By dragging each component up and down vertically, the user can control the weights to their own custom fit.