Reimplement wave AI, split out some UI code into a ui module, update TODO

src/main/java/gg/malloc/defense/engine/WaveManager.java

@@ -0,0 +1,55 @@
+package gg.malloc.defense.engine;
+
+import gg.malloc.defense.model.Wave;
+import gg.malloc.defense.model.Game;
+
+public class WaveManager {
+  int m_currentWaveNum = 0;
+  int m_currentBatch = 0;
+  Wave m_currentWave = null;
+  Game m_game;
+
+  public WaveManager(Game game) {
+    m_game = game;
+  }
+
+  public void reset() {
+    m_currentWaveNum = 0;
+    m_currentBatch = 0;
+    m_currentWave = null;
+  }
+
+  public Wave currentWave() {
+    return m_currentWave;
+  }
+
+  public int currentWaveNum() {
+    return m_currentWaveNum;
+  }
+
+  public int currentBatchNum() {
+    return m_currentBatch;
+  }
+
+  public double progress() {
+    return (double)m_currentWaveNum / (double)m_game.getWaveCount();
+  }
+
+  public boolean isLastWave() {
+    return m_currentWaveNum >= m_game.getWaveCount();
+  }
+
+  public boolean isLastBatch() {
+    return m_currentBatch >= m_currentWave.batchCount();
+  }
+
+  public void nextBatch() {
+    m_currentBatch += 1;
+  }
+
+  public void next() {
+    m_currentWaveNum += 1;
+    m_currentBatch = 0;
+    m_currentWave = m_game.getWave(m_currentWaveNum);
+  }
+}