Support Turn Time

[brettbates]

1. a4 {12 that took 12 secs}

Officially there is no PGN idea for clocktime, so different places have implemented different ways.

E.g

{12 This took 12 secs}
{preamble [%clk 0:0:12] took 12 secs}

For now will leave this up to the user to implement timing as it is not part of the pgn spec. Later may look at supporting this as the need arises.