Plot Updates #132
Description
There are some simple plotting updates that would be nice to add for 1.0:
- make the axis labels match the log status
- be able to pass labels / use a legend for plot_spectra
- be able to pass multiple frequency axes to plot_spectra
- make the default line width thicker
- split out the aesthetics for the spectrum plots (so they don't get re-run per line on the same plot, and so as to become customizable)