Snake game : Now removes piece from grid when moving block.
Adding Red Snake Trail.  Press Space to change color.
Restructuring classes to work with Tetris and Snake game.
Tail Functionality Added.
Tail fixxed to no longer disappear on movement tap.
Merge branch 'snakeGame'
WIP clear row.  Simplified render grid logic onupdate; SetBlock flips gridUpdateB == true.  Cleaned up Set and Get blocks to use Vec2.