feat: add elapsed time, fix bugs

src/main/java/eu/midnightdust/yaytris/game/Space.java

@@ -66,6 +66,10 @@ public class Space {
         Set<Integer> completedLines = new TreeSet<>();
         for (int line : lines) {
             if (line >= getMapHeight()) continue;
+            if (line < 0) {
+                Tetris.stopGame();
+                return;
+            }
             Color[] newBlobs = tetromino.getLine(line);
             for (int i = 0; i < newBlobs.length; i++) {
                 if (newBlobs[i] == null) continue;
@@ -85,6 +89,7 @@ public class Space {
             }
         }
         increaseScore(combo);
+        this.spawnTetromino();
     }
 
     public void increaseScore(int amount) {