Radnom segmentation faults in "02_jump_game.py"
When running the example "02_jump_game.py" with Python 3.7.3 on Debian 10, segmentation faults happen seemingly at random. 

I tried tracing the segfaults using [this method](https://stackoverflow.com/a/2663863/11617800):
```
line, 02_jump_game.py:96
line, 02_jump_game.py:97
call, /usr/local/lib/python3.7/dist-packages/pyxel/__init__.py:769
line, /usr/local/lib/python3.7/dist-packages/pyxel/__init__.py:770
line, /usr/local/lib/python3.7/dist-packages/pyxel/__init__.py:774
return, /usr/local/lib/python3.7/dist-packages/pyxel/__init__.py:774
Segmentation fault
```
