* 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.
- Update libzint support for 2.15 as new baseline version, removing support for earlier versions, avoiding '#ifdef'-hell
- Based on #186
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Co-authored-by: gitlost <burmartke@gmail.com>
Jaye Evins