Sod's: move reference to the bottom
Sod's test problem, reference
Add shock tube sketch
Edit shock-tube notebook throughout
Final edits, shock-tube notebook
remove muscl notebook for merge into master
Merge branch 'master' into wave_merge

Conflicts:
	lessons/03_wave/03_05_Sods_Shock_Tube.ipynb
Merge branch 'wave_merge'