Add Aseba examples (v2)


I encountered several people with the need for a custom GUI to communicate with Aseba nodes. There is no examples readily available to bootstrap the process, even if one can found inspiration inside asebacmd and alike. Moreover, several example codes may be dispersed through out the source tree.

Here, I create an /example/ directory, and populate it with a very minimal GUI. The existing Python example script, previously in /medulla/, is also moved to the new directory. A brief readme documentes the stuff.

From v1:
- Rebased on current devel branch
- Moved examples to 'examples/clients'