Upped version to 0.0.3
Refactor html, css out of the js file
Added file input as an alternative way to import the keystone image in as opposed to drag and drop
Moved most overlay CSS styles into stylesheet.

The opacity setting was not moved into the stylesheet because it should be configurable via the view helper or, in the future, through the GUI.

I want to avoid developers forgetting they entered a custom opacity setting through CSS and deploying it to production.
Added visual buttons to nudge keystone image around the viewport