New Tutorials on GitHub

I wrote ipython notebook tutorials for some new packages I've been learning:

• pyds9 (call ds9 image plotting tool from python)
• pyregion (use ds9 regions files in python, including image filtering)
• seaborn (pretty plotting add-on to matplotlib, makes nice density plots).  Well actually, it's a mashup of Astropy, Pandas, and Seaborn:  the tutorial downloads a machine-readable table from an ApJS journal article, reads it in with astropy, converts it to a Pandas data frame, filters the data, and then plots a density plot using seaborn.

 In case they're useful for others, I put the tutorials on github.