Kiko - fix too slow in Linux - Mac

The game Kiko runs too slow on Linux and Mac, due to a bad selection of time provider.
A workaround for this requires only a one line change:
in kiko/base.py, near the begining, change the line
time_service = time.clock
to
time_service = time.time

Bug reports and comments wellcomed.
(thanks Zero|Byte from #pyweek for testing)