Create a method to spawn random tetromino

[martinreinok]

This is probably a queue of objects of x amount, at the end of game update loop the queue should be filled back up if size() is not x (if any blocks were removed). The queue should be rng suffled.

[martinreinok]

This was done withing the Tetromino class instead. A new method createRandomTetromino will initialize the object with a random tetromino. The class was reworked a bit, all relevant methods were made into void.