Pygame-menu

- Update README and documentation.
- Fix position calculation for python 2.

<a href="https://github.com/ppizarror/pygame-menu/blob/v2/README.md">Documentation</a>

- Color fix when a user types too fast.
- Fix menubar issue, 116.

<a href="https://github.com/ppizarror/pygame-menu/blob/v2/README.md">Documentation</a>

- New color input widget, supports rgb and hex formats, 100.
- `add_option` deprecated, replaced by `add_button`, 90.
- Fixed textinput default issue, 86.
- Fixed joystick initialization issue, 86.
- Added cross in menu bar, 89.
- Several refactorings.

<a href="https://github.com/ppizarror/pygame-menu/blob/f855ddd9f32b0829b76d032cbdc8be5acd6a8bad/README.md">Documentation</a>

- Sound fixes.

- License update.

- Improve font rendering.
- Added *font_size* optional parameter to *add_option*, *add_selector* and *add_text_input*.