Removed test for insufficient players in game_checkCard()
Refactored game_findNextAllowedCard() and game_findPreviousAllowedCard(). Introduced findAllowedCard() helper.
Added test for game_findNextAllowedCard(). T3.1
Added test for game_findPreviousAlloedCard(). T3.2
Merge branch 'Test-improve' into develop
Fix T3