Create a new `Overlay` class

[dkrutsko]

Since #2 is no longer being implemented, an alternative class needs to be developed in order to solve the initial problem. The Overlay class will contain functions relating to the creation and manipulation of overlay windows. These overlay windows are transparent and are designed to be positioned in front of other windows. Once positioned, developers are able to draw images on the overlay window, "augmenting" what is below it. Since images are the only way to render to the overlay window, an external rendering library will need to be used, which keeps robot in-scope.