Re-add 'Cowardice' and 'Aggressiveness' UCI options

I have lost my bet with Jean-Paul, so now I re-add
the two options...and I am glad of it :-)

No functional change.
Tweak some UCI parameters

According to Jean-Paul this setup should be stronger
than default.

And SPRT test seems to confirm it:

At fast TC 15"+0.05
ELO: 3.33 +-2.7 (95%) LOS: 99.2%
Total: 25866 W: 5461 L: 5213 D: 15192

At longer TC 60"+0.05
ELO: 7.27 +-5.0 (95%) LOS: 99.8%
Total: 6544 W: 1212 L: 1075 D: 4257

bench: 5473339

Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Rescale UCI parameters to 100

And correspondingly modify internal ones
to compensate it.

No functional change.