NPE after returning to started game from home button

[ghostbuster91]

How to reproduce:
1.start app
2.start game
3.when will be not your turn click home button ( this could be in player's turn too )
4.return to the game

stacktrace:
//java.lang.NullPointerException: Attempt to invoke interface method 'java.util.ArrayList com.google.android.gms.games.multiplayer.turnbased.TurnBasedMatch.getParticipantIds()' on a null object reference
//at com.ordonteam.hanabi.activity.GameActivity.getPlayersNumber(GameActivity.groovy:105)
//at com.ordonteam.hanabi.activity.GameActivity.initiateMatchResult(GameActivity.groovy:96)
//at java.lang.reflect.Method.invoke(Native Method)
//at java.lang.reflect.Method.invoke(Method.java:372)
//at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:90)
//at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:324)
//at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1208)
//at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1075)
//at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1017)
//at groovy.lang.Closure.call(Closure.java:423)
//at org.codehaus.groovy.runtime.ConvertedClosure.invokeCustom(ConvertedClosure.java:51)
//at org.codehaus.groovy.runtime.ConversionHandler.invoke(ConversionHandler.java:103)

[OrdonTeam]

Please check if this bug still occurs.
Possible fix in 516ae82

[ghostbuster91]

it still occurs.
Procedure to reproduce: start match, when it wont be your turn click sqaure, circle, square -> hanabi.