Handicap speed calculation

[tkurki]

In a race it could be interesting to see how boats are performing according to the handicap rules of the race. Some handicap systems are easy enough, for example http://en.wikipedia.org/wiki/LYS_(sailing).

There should be an option to color code the boat markers with colors showing if they are doing better or worse than the reference boat. The ranking list could show also the corrected speed.

See also #3.

SignalK schema should have an extension point for defining the handicap values for a boat in effect during a race (note: the handicap changes over time and can depend on sail inventory on board/allowed in a race).

[keesverruijt]

One race committee I am on is considering allowing entry of boats in multiple classes, for instance IRC and a one design class. Maybe we should cater for this.