Add tile group with example, rename setScollBar to setScrollbar

[mgord9518]

This PR also includes the following other changes:

• Removal of old comments
• Formatting with zig fmt
• Refactoring of a couple lines to make them more readable
• Addition of Group.setScollbarSize method
• Fix a couple types

The thinking behind allowing signed X and Y values allows widgets to be pushed off-screen, which makes sense for animations and whatnot. However, negative sizes are undefined, so negative W and H should never be allowed. My guess as to why FLTK uses int for all 4 values is probably just because it's an easier type to work in C++ with than unsigned int without requiring constant casting

[MoAlyousef]

Thanks for this.