Converted ShatteredPD to Build from Gradle

Major Changes:
- Shattered now builds effortlessly either from gradle CLI or android studio
- Much better dependency management through gradle (although it's not really used atm)
- Separate PD-classes repo is now SPD-classes module within main repo

SPD-classes/src/main/java/com/watabou/noosa/Scene.java

@@ -0,0 +1,81 @@
+/*
+ * Pixel Dungeon
+ * Copyright (C) 2012-2015  Oleg Dolya
+ *
+ * Shattered Pixel Dungeon
+ * Copyright (C) 2014-2016 Evan Debenham
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ */
+
+package com.watabou.noosa;
+
+import com.watabou.input.Keys;
+import com.watabou.utils.Signal;
+
+public class Scene extends Group {
+	
+	private Signal.Listener<Keys.Key> keyListener;
+	
+	public void create() {
+		Keys.event.add( keyListener = new Signal.Listener<Keys.Key>() {
+			@Override
+			public void onSignal( Keys.Key key ) {
+				if (Game.instance != null && key.pressed) {
+					switch (key.code) {
+					case Keys.BACK:
+						onBackPressed();
+						break;
+					case Keys.MENU:
+						onMenuPressed();
+						break;
+					}
+				}
+			}
+		} );
+	}
+	
+	@Override
+	public void destroy() {
+		Keys.event.remove( keyListener );
+		super.destroy();
+	}
+	
+	public void pause() {
+		
+	}
+	
+	public void resume() {
+		
+	}
+	
+	@Override
+	public void update() {
+		super.update();
+	}
+	
+	@Override
+	public Camera camera() {
+		return Camera.main;
+	}
+	
+	protected void onBackPressed() {
+		Game.instance.finish();
+	}
+	
+	protected void onMenuPressed() {
+		
+	}
+
+}