Fit analysis matrix element handling

[phockett]

Mainly working but:

• Possible m=+/-1 ordering switch on some tabulations? (Arose during N2 results testing.) May be due to relabelling routines assuming ordering? TBC.
• Var names for paramPlot, need setting otherwise get linked 'value' plot y-axes in layouts (although setting .opts(shared_axes=False) will fix at plot).
• fit._aggUtil debug. OK, see cf0ac4b