Canonical unit representation --> CellML units issue: multiplier value?

[nickerso]

The model compactor code uses the canonical units representation from CUSES to determine unit equivalency and will serialise these canonical units to the generated model.

An initial look at the generated units shows that the multiplier value may not be correct. Need to look into exactly what the value means in the base unit instance and how it should be represented in the CellML units being generated.