v0.07 - MusicManager improved

This update (v0.07) covers the following: 

• We can add a music for the scene/level. This way we have a song for the town and  a song for the shore. 
• If the song is the same in two scenes, then the manager will not stop the song and play it again from the beginning. We can see this if we start in the town and then we go into the church.