teamspeak2 plugin: Add collection of packet loss.

teamspeak2 plugin: Add collection of packet loss.

I added another interesting gauge to the sets of values which get fetched. The
average package loss in percent. I used the percent type from types.db...not
really intuitive when looking at the folders but it works. I also tried to add
something to the manpage...but I wasn't able to test it because the manpages
just don't install with make install...