v0.7.5d: added various safety checks

SPD-classes/src/main/java/com/watabou/noosa/audio/Music.java

@@ -22,6 +22,7 @@
 package com.watabou.noosa.audio;
 
 import com.badlogic.gdx.Gdx;
+import com.watabou.noosa.Game;
 
 public enum Music {
 	
@@ -50,10 +51,15 @@ public enum Music {
 			return;
 		}
 		
+		try {
 			player = Gdx.audio.newMusic(Gdx.files.internal(assetName));
 			player.setLooping(looping);
 			player.setVolume(volume);
 			player.play();
+		} catch (Exception e){
+			Game.reportException(e);
+			player = null;
+		}
 		
 	}
 	

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/mechanics/Ballistica.java

@@ -52,10 +52,15 @@ public class Ballistica {
 	public Ballistica( int from, int to, int params ){
 		sourcePos = from;
 		build(from, to, (params & STOP_TARGET) > 0, (params & STOP_CHARS) > 0, (params & STOP_TERRAIN) > 0);
-		if (collisionPos != null)
+		if (collisionPos != null) {
 			dist = path.indexOf(collisionPos);
-		else
+		} else if (!path.isEmpty()) {
 			collisionPos = path.get(dist = path.size() - 1);
+		} else {
+			path.add(from);
+			collisionPos = from;
+			dist = 0;
+		}
 	}
 
 	private void build( int from, int to, boolean stopTarget, boolean stopChars, boolean stopTerrain ) {

core/src/main/java/com/shatteredpixel/shatteredpixeldungeon/windows/WndGame.java

@@ -67,7 +67,7 @@ public class WndGame extends Window {
 		}
 
 		// Restart
-		if (!Dungeon.hero.isAlive()) {
+		if (Dungeon.hero == null || !Dungeon.hero.isAlive()) {
 			
 			RedButton btnStart;
 			addButton( btnStart = new RedButton( Messages.get(this, "start") ) {