Add time odds on time control dialog

[pychess]

Original issue 744 reported by gbtami 2012-12-30

I like to play with time odds against stronger engines.

[vgupta2507]

What do you mean by time odds :

1. To have multiple time controls in a single game. For example: 1 hour for first 40 moves and 30 additional minutes for following game.
2. To have different time controls for both players. For example: I have 10 minutes in total while my opponent has 5.

[gbtami]

1. is issue Advanced Time Control #1015 and issue Add FIDE/tournament time controls #755
   Time odds is 2). We have only one (minutes, gain) time control for a game now but having two pairs would be better sometimes.