Plot systems

[jnothman]

This new plot-systems command is now very flexible although messily written. It should be played around with and we should see what's good for a TAC summary in paper or web site form.

TODO:

• [ ] Documentation
• [ ] String substitution for display
• [ ] sort by name should be case-insensitive
• [x] Systems and measures on one plot (e.g. heat map)
• [x] Precision and recall on row/col plot
• [x] custom figure size? (less important now that interactive fine-tuning of figures is possible)
• [ ] ignore no-variance measures in CompareMeasures

[jnothman]

Also, this does not currently have a way to show all measures and systems on a single plot, which could be done with a heat map, or with systems indicated by markers in measure-specific rows or vice versa.

[jnothman]

I think I'll merge this soon...