Rename configuration folder

I renamed the configuration folder from etc to conf for no big reasons
but for aesthetics.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>
Add docstring for events, notifier and util module

I wrote docstring for the three utility modules, namely events, notifier
and util. I noticed that all of the three only encapsulate one class and
it might be useful to merge one or two of them in the future.

Signed-off-by: Konrad Reiche <konrad.reiche@gmail.com>