[jqiutpmb] Byoyomi for correspondence chess

The byoyomi time control used in go 囲碁 seems to make sense for correspondence chess.  Even though time may be passing, the player is thinking only for a minuscule portion of the time between moves, so it doesn't make sense for the clock to be advancing the entire time.

Set the first period to 48 hours to minimize time zone and work schedule differences, and further periods to 24 hours.

Little Golem has probably considered this.

Previously: http://kenta.blogspot.com/2013/12/yrxoydqs-correspondence-blitz-chess.html