Programmatically Position enhancedGraphics app Images

[cannin]

After #19 learn to programmatically position enhancedGraphics app images. We will need an algorithm for how to position many of these annotation data images.

[thepritam]

@cannin We can do it programmatically. There is property NODE_CUSTOMGRAPHICS_POSITION_ which we can set at any side of the node. We have to use discrete mapping to do it.