Mixtape

- Made Mixtape compatible with resourcepacks!
- you can now create a `music_list.json` file in `resourcepack/assets/mixtape` structured like this to make them correctly show up on music toasts.
```json
{
"calm1": {
"name": "Minecraft",
"artist": "C418",
"album": "Minecraft - Volume Alpha"
},
"calm2": {
"name": "Clark",
"artist": "C418",
"album": "Minecraft - Volume Alpha"
}
}
```
- you can now create an `album_list.json` file in `resourcepack/assets/mixtape` structured like this with x and y matching coordinates of 300x300 squares on `resourcepack/assets/mixtape/textures/gui/album_covers.png`
```json
{
"Album": {
"x": 0,
"y": 2
},
"Album2": {
"x": 1,
"y": 2
}
}
```
- Resourcepacks that add music without having a music or album list file will no longer crash the game.