* Bulk replaced tabs with spaces
* Bulk removed trailing whitespace from lines
* Replaced c-style comments with c++-style comments in file banners
* Replace nested namespace definitions with single concise definitions (C++17), this keeps the indentation more manageable
* Cleanup ordering and spacing of include directives
* Bulk renaming of header file extensions from '.h' to '.hpp'.
* Update CODING-STYLE.md
* Update target_compile_features from cxx_std_11 to cxx_std_20.
* Refresh .clang-format file. Still needs a lot of tweaking.
- Not all Qt::CursorShapes are supported on all platforoms
- e.g. on Wayland (Ubuntu 24.04) Qt::SizeAllCursor is not available and
falls back to its arrow cursor
- added built-in Crosshair and Move cursors, so that they should be available
across all platforms
- Redesigned existing object creation cursors
- Crosshairs are now 3-pixels wide
- Added white outlines to all cursors to aid in visibility against diverse
backgrounds