Remove zoom functions

[jgadsden]

The zoom feature and buttons make it possible to lose parts of the diagram. Because the jointjs 'scale' only scales the elements and not the paper, if elements are dragged or placed when zoomed out then these can be inaccessible when zoomed back in. This results in these elements only being accessible when zoomed out which is very difficult to use.
Until the zooming, scaling, panning and paper size can be fixed it is best to remove the zoom feature. Issue #95 has been raised to reinstate the zoom feature

[jgadsden]

Note that this issue will also deal with 'Scaling of icons behaves strangely after using the zoom function' #73 and 'It's impossible to zoom in on items on the right or bottom of the diagram' #72