NPE on Android in SolveScreen

[thomaswp]

This has been reported by Android users unpredictably on the SolveScreen:

The odd thing is that if PlanN is functioning correctly it seems this would be impossible. It would require paint() to be called before init(). Of course were that the case we would expect other null pointers before this one.

java.lang.NullPointerException
at tuxkids.tuxblocks.core.solve.NumberSelectScreen.paint(NumberSelectScreen.java:415)
at tripleplay.game.ScreenStack$Transitor.paint(ScreenStack.java:379)
at tripleplay.game.ScreenStack.paint(ScreenStack.java:299)
at tuxkids.tuxblocks.core.TuxBlocksGame.paint(TuxBlocksGame.java:152)
at playn.core.Game$Default.tick(Game.java:101)
at playn.android.AndroidPlatform.update(AndroidPlatform.java:220)
at playn.android.GameViewGL$1.onDrawFrame(GameViewGL.java:60)
at android.opengl.GLSurfaceView$GLThread.guardedRun(GLSurfaceView.java:1516)
at android.opengl.GLSurfaceView$GLThread.run(GLSurfaceView.java:1240)