Add citation and licensing info.
Update custom.css styling.

Also: more detailed README.
Merge branch 'master' of github.com:ketch/hyperpython

* 'master' of github.com:ketch/hyperpython:
  Update README.md
  Remove non-working Mathjax stuff.
  Update paths to reflect new directory structure.
  Update README.md
  Use local Lax-Friedrichs flux in lesson 3 part 2.
  Update README.md
  Update README.md

Conflicts:
	Lesson_00_Python.ipynb
	Lesson_01_Advection.ipynb
	Lesson_02_Traffic.ipynb
	Lesson_03_High-resolution_methods.ipynb
	Lesson_04_Fluid_dynamics.ipynb
	Lesson_05_PyClaw.ipynb
	README.md
	custom.css