Feature request: support for line graphs

[jzadra]

It would be great to add support for line graphs.

The data could be represented by point data, with the user specifying the frequency of points for each axis.

Color detection would be important too if there are multiple lines designated by color (or line type).

[daniel1noble]

Thanks @jzadra . @joelpick and I can look into this. In practice you could still treat these as scatter plots and then just click points along the line. You can then fit whatever function to that data to get, say, the slope.