Removed support for different outputunits

The conversion and updating of having the choice to switch outputunits was
just making the program messy and wasn't used for any real purpose anyways
Normalised lines according to a current amplitude maximum

Now each line stores their own amplitude maximum and both lines are
plotted within the greatest of these two maximum. Works for first and fourth
tone but still issues with the second. Segmented regression is still needed
for the third tone to work. Fixed #10.
Merge branch 'iss10'