makes a.button style usable for input.button as well
renames acceptsRatingMin/Max to accept (no s)
sets _oldRatings to players' current ratings in server Game constructor
adds getGames and getChallenges to Application so modules that start after the server is connected can get the current games and challenges
renames LightsquareUi to Lightsquare in main
adds getRating to server User
adds more wiring up of challenges to home page