Implement log scale (and other scales)

[DunklesArchipel]

In order to capture a log scale we could implement a new tag <scale> in the axislabel in the svg file such as, y1: <scale> <value> <unit>. Examples:

• y2: log10 100 A/cm2
• y2: log 100 A/cm2.
• The inverse of a quantity, such as 1/T could be y2: inv 0.1 T or y2: power(-1) 0.1 T