#4 Q1, Q3, IQR not displayed

[Mark Livingstone]

Q1 and IQR exist in code but are not displayed despite having an IQR menu option.

Q3 does not get calculated at all AFAICT but can be calculated trivially using Q1 + IQR

Q1, Q3 then need to be exposed

[Mark Livingstone]

Fixed as of SVN submit #29!