Fix exit, improve baseimage (v4)

[ppizarror]

• Fixes Menu Quit Error : SystemExit on VS Code #251, BaseImage Spam #252.
• Improves docs.
• Added BaseImage methods get_drawing_mode, set_drawing_mode, get_drawing_offset, and set_drawing_offset.
• New PYGAME_WINDOWCLOSE event locals.
• Fix several typing issues.
• Removed **kwargs from Menu constructor.
• Renamed touchscreen_enabled to touchscreen in Menu constructor.
• Improve computation of max/min widget position.
• Improved widget positioning on Menu centering.
• New Menu method get_height and set_title.
• New MenuBar widget method get_title_offset.
• Fixed ScrollBar constructor parameter onchange.

[codecov]

Codecov Report

Merging #257 (4becb23) into master (6707e1a) will increase coverage by 0.48%.
The diff coverage is 91.37%.

@@            Coverage Diff             @@
##           master     #257      +/-   ##
==========================================
+ Coverage   86.72%   87.20%   +0.48%     
==========================================
  Files          46       45       -1     
  Lines        5332     5376      +44     
==========================================
+ Hits         4624     4688      +64     
+ Misses        708      688      -20     

Impacted Files	Coverage Δ
pygame_menu/__init__.py	100.00% <ø> (ø)
pygame_menu/scrollarea.py	80.24% <ø> (+3.70%)	⬆️
pygame_menu/sound.py	86.54% <ø> (ø)
pygame_menu/themes.py	87.27% <0.00%> (ø)
pygame_menu/utils.py	100.00% <ø> (ø)
pygame_menu/widgets/widget/button.py	100.00% <ø> (ø)
pygame_menu/widgets/widget/colorinput.py	93.57% <ø> (ø)
pygame_menu/widgets/widget/image.py	94.33% <ø> (ø)
pygame_menu/widgets/widget/label.py	95.65% <ø> (ø)
pygame_menu/widgets/widget/none.py	98.70% <ø> (ø)
... and 20 more

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