make share ratio a more meaningful number

[user]

On /tunnels I can see the amount of data transferred through tunnels we participate in, so it should be trivial to make 'share ration' a bit more meaningful.

Currently it takes only the number of hops we use and tunnels we participate in into account, no matter if we actually forward traffic at all or not.
Therefore, even with a share ratio >1 we could not be contributing to the network.

Suggestion:
new_shareRatio = sqrt(old_shareRatio * forwData5Min/(totalData5Min-forwData5Min))

This takes into account both, the amount of traffic we forward for others and that covers up our own traffic, plus the amount of different tunnels we service, providing heterogenity and spread

[user]

or even plain minimum:

new_shareRatio = min( old_shareRatio , forwData5Min/(totalData5Min-forwData5Min) )