Plotter: Add tick label precision to dintinguish adjacent labels

Created by: jasonpfox

Resolves #301 (closed)

Previous precision limits guaranteed seeing at least one digit of major tick mark values; however, this was not enough to tell them apart, and all major tick marks could display the same value without precision to tell them apart. This change increases minimum precision based on distance between the major tick marks to ensure that adjacent major labels can be distinguished from each other.

Note the colorbar tick labels for similar random test data sets before and after the change