finish activity: layout updates for action buttons
board: cache details player and only update when rotating board
optimize: replace for-each loops with for loops to reduce memory consumption and gc runs

for some reasons, a  "for (Object o: Collection)" loop creates garbage that needs to be collected, while
a "for (int i = 0; i < size(); i++)" loop does not. Replace critical loops in the rendering subsystem by
the explicit iterator one to reduce number of gc runs.