Enable a 3x3 matrix summary

[ThomUK]

Plot a 3x3 matrix summary of Variation vs. Assurance.

[ThomUK]

Now that multiple output types (html, pdf, csv) can be specified (v0.2.0), this could be multiple new report types:

• html_full_3x3 - the full standard report with this 3x3 at the start
• pdf_full_3x3 - as above in pdf format
• html_3x3 - a report containing only the 3x3
• pdf_3x3 - as above in pdf format