Font value

We need the ability to define font as a value that can be used as an input for Text nodes. I want to be able to provide the Font as a parameter, which is complicated now, because the Text node is usually in the middle of my nodes graph.

Start by locating the Text node and the value types used for node inputs, then trace how parameters move through the node graph. Done means a Font can be defined as a value and supplied as an input to Text nodes, including when the Text node is in the middle of a graph.

Written by the indexing model from the issue text.