Update the Solar System notebook for Skyfield 0.1

And, enable inline screenshots for the iPython Notebook viewer.
Add text to the 3D Solar System notebook
Make space behind the Solar System black
Add screen captures to Solar System notebook

This will let people view it online through the IPython Notebook Viewer
and see an example of the resulting 3D window, to give them a better
idea of whether they are interested in trying out the notebook live on
their own system.
Switch 3D Earth Satellites to Skyfield

Wow, the interface is still very clunky, but even with Skyfield 0.1 it
is now possible to get Earth-satellite positions directly from its
interface instead of having to make raw calls to the sgp4 library.
Switch to precomputing satellite positions

Otherwise the animation runs too slowly. Also, fixes #8.
Add inline images to 3D satellite notebook
Merge branch 'master' into jep-dev-dev
Automate pulling masses and radii from HORIZONS
Rename HORIZONS notebook from "Misc-" to "Utils-"
Add names to HORIZONS masses and radii
setup.sh and setup.bat: Eliminated deprecation warnings by specifying exact version of some packages.

More particularly:
    pip install mayavi==4.3.0
    pip install traits==4.3.0
    pip install traitsui==4.3.0
    pip install pyface==4.3.0

This is not an elegant solution, but the perfect is the enemy of the good
enough. So first I make it work, then I hope to refactor.
Merge remote-tracking branch 'upstream/master' into jep-dev-dev