Pyxel

- Add the quit key to Example 8
- Fixed the key input detection at the first frame
- Fixed the way to quit the Pyxel application

- Changed the way to quit the Pyxel application

- Updated the README in Korean
- Updated the installation instructions in the READMEs
- Changed color names along the new palette
- Changed to optimize an animated GIF with Gifsicle

- Fixed the way to quit the Pyxel application
- Fixed Python version check

- Updated the installation instructions of the READMEs
- Added the link to the Discord server to the READMEs
- Added variable frame rate support for animated GIF
- Added the mouse_wheel variable
- Added the fullscreen option to the init API
- Changed the way to quit the Pyxel application
- Removed the border options of the init API
- Changed the required version of Python

- Improved the animated GIF making method
- Added the README in Portuguese
- Fixed to work with Python 3.7 on Windows
- Changed the color change shortcuts to ignore the alt keys