QC plot improvements

[bpbond]

• Core mass plot - normalize all relative to 100% (initial starting mass)?
• CO2 and CH4 fluxes - plot by incubation day, not date?
• CV of CO2 and CH4 observations - by date AND incday
• Would like 9 most core means AND 9 most variable treatment means

[bpbond]

Dupe of #11