Interactive-3D-Earth-Satellites.ipynb: Added markdown cell about interacting (navigating) mayavi with keyboard and mouse.
INSTALL-xubuntu-12.10: Checkout tag instead of SHA1 hash. Should be easier and more meaningful to support.
INSTALL-xubuntu-12.10: Polished comments.
Interactive-3D-Earth-Satellites.ipynb: Polished wording in a markdown cell
An-Introduction--Notebook-Features.ipynb: Avoided deprecation warning about sympy printing.
Merge pull request #5 from james-prior/jep-dev

Several updates and bug fixes.
Switch from "yes |" to simpler "-y" option
Switch to install of Skyfield from Package Index