Add graph labeling and refactor + debug plot code

Improve graph colours and layout. Create plotlines (need debugging).
Some data points are messed up and need debugging, extra runs added where
they shouldn't be
Add graph labeling for batch quantities

Refactor plot function in production-scheduler to show the batch
quantities in the graphed data. Remove a bug where extraneous trend lines
were plotted.
Clean up and annotate graph; fix menu logic

Add an accurate and neat-looking trend line to the plot function in
production-scheduler. Fix menu logic which caused the program to crash
when selecting a schedule outside of the range. Provide additional
feedback when generating the report
Merge branch 'master' of https://github.com/johnsaigle/production-scheduler