replace errors.new(fmt.sprintf()) with fmt.errorf, use strings.builder
instead of string concatenation in loop, fix defer in loop issue,
preallocate slices where size is estimable
- replace proprietary license with bsd 3-clause
- update all go file headers with new retro terminal style
- add header-check github action to enforce license headers
- completely rewrite readme to be modern, sleek, and lowercase
- fix broken badges
