major OVERHAUL

[dvdcjw]

made this project way more practical, efficient and maintainable

Alters:

• Clicking on checkboxes now will not cause the program to sleep for 0.15 seconds.
  Instead, to prevent multi-triggering when held down, the program checks if the checkbox was pressed in the last frame to avoid potential and obvious problems.

• CALLBACKS

Users no longer need to detect if the button is pressed or if the checkbox is enabled in the main loop.
Instead, users now assign a function to the callback argument when defining the widget.
Once the callback is triggered, the function will be called immediately and automatically.

• Fixed text for checkboxes and buttons.
  Now, the text argument is usable for checkboxes and buttons.
  When defining, the user would only need to text=str when defining the widget
  Then, the text will automaticly be placed.
  (In the button and beside the checkbox. )

• Text alignments
  Both horizontal and vertical alignments for text are supported.

• Fixed multi-triggering
  In the past, the corresponding function would be triggered per frame when a situation was reached (a button was pressed down, a checkbox was checked, etc.).
  Now, with the callback, the required function will only be triggered once (when the button is initially clicked, and once when the checkbox is checked).

• More managable widgets
  Now, widgets will be saved in a list,
  This enables the library to automatically render them, handle callbacks, and avoid multi-triggering.

• Code format overhaul
  Optimised the source code to follow PEP8, so it's more maintainable and readable

• Compatible with previous projects
  Although the new approaches are much more efficient and recommended,
  previous programs using this library will still run smoothly.