Simplify the get_extra_paths method.

[thefunny42]

The default behavior of get_extra_paths did too much for me: I don't want to have uwsgi include all parts folder as a pythonpath, because my buildout installs different applications and scripts. This end-up creating an error in my application, because of conflicting packages.

I just removed this automatic behavior for the moment: I think if you need to do this, you can do it manually by specifying those paths in the extra-paths option. Explicit is better than implicit after all.

I updated the blacklist to include more buildout options: I got an unwanted find-links in my uwsgi configuration.

I reformatted a bit the code, to remove trailing whitespaces, and keep it in the 80 columns norm.