Preparing for 0.4 and updated gallery

[Stéfan van der Walt]

Hi all,

I think we are basically ready to tag 0.4!  If you know of any issue
that needs to be addressed urgently, let me know.

The gallery is also filling up very nicely!

http://scikits-image.org/docs/dev/auto_examples/index.html

E.g, you'll see the contour finding by Zach Pincus that was merged
today, and the grey-level co-occurrence matrix work by Neil Yager.

According to Ohloh, we now have about 10,000 lines of Python code, vs,
e.g., scikit-learn's 30,000.  Keep it coming!

Cheers
Stéfan