Call for Levels! How you can participate here

This release is a bit poor on levels. But the community can help, thanks to the built-in level editor and the power of pull requests!

### Call for Levels -- Instructions

1. Open the level editor in Propan.
2. Build your shiny new level with the editor.
3. Press S to save it to a new file in your levels folder (called "#.json", where `#` is the level number).
4. Edit the new file with a text editor to include an interesting name (preferably allusive to the level you made), in the "name" property of the JSON object.
5. Upload your level [with this link](https://github.com/Enet4/propan/upload/master/levels), or create a new branch that includes the new file if you know the drill.
6. Create a new pull request with that inclusion.

Once that's done, I will try it myself and possibly provide feedback for improvements. Once merged, the level will be available to everybody else, and will come with future releases of the game. Good job!

### Hints for Level Making

- **Have an objective**: although the game editor does not force you to include a finish flag, please place one in an accessible place. All gems should be attainable as well.
- **Avoid overlapping walls and objects**: this is possible, but it doesn't look very nice.
- **Do not be excessive**: the game isn't very well optimized at the moment, so please do not make too many walls or other objects. For building pathways, consider using the least number of walls required for the intended effect. For instance, walls that the ball can never hit can be removed.
- **Make it challenging**: A good level has some quirks that will stop players from beating the level easily, but still drive them into trying again. A nice rule of thumb is to try beating your own level in at most 3 tries. If you cannot do so, then it's probably too hard.
- If you find bugs in the game while editing or trying a level, you are invited to file an issue [here](https://github.com/Enet4/propan/issues/new). Thank you!