Graph Object Update and bug fixes

Update the program to use a graph object as the main way to manipulate
the view. Easily add nodes and links.

Fixed a bug in the link QML where when 2 nodes were placed vertically
the link would rotate by 90 degrees.

Updated node, link, and graph methods are made available.
Revert "Graph Object Update and bug fixes"

This reverts commit 9951e96389f47c76d226a23c7d99ab1fb2965430.