Scripts in `scripts-article` should be fully integrated into the package

The idea on providing a single set of scripts to run the toolchains in the package is good. Unfortunately, these scripts are not integrated well into the package, nor are similar to the approach adopted by other "base" frameworks (such as bob.bio.base, bob.pad.base or bob.dia.base). Here are a few key points to address for now:

1. Instead of having multiple scripts, just create a single one with options. For example, call it baseline.py.
2. Make it a proper entry points
3. Move the README into a section of your documentation
4. Instead of using os.system() calls, just execute the main() function of the modules
5. Optionally, add gridtk support for allowing the user to run things in parallel

This will make the scripts simpler and avoid all the management you have inside them to locate things. It will also make it possible to re-run your baselines in a reasonable amount of time (if 5 is also addressed).