Fixes:
- Partial support for #rrggbbaa CSS Level 4 colors with alpha (@charlymz)
- Avoid infinitely duplicating parts when extending selector (@cyberalien)
- Fix rooted SCSS URIs normalized incorrectly with double slashes (@evanceit)
- Coding style updates (@brainfoolong)
- Interpolation support selector (@jakejohns, @Cerdic)
- Improve error messages (@gabor-udvari, @Cerdic)
- Fix font shorthand syntax (@JanST123, @Cerdic)
- Peephole optimizations (@oyejorge, @Cerdic)
- Compiler: change some private properties/methods to protected (@cyberalien)
- Fix for "continue" causing PHP 7.3 warning (@darkain)
- Fix error thrown from strpos if needle (basePath) is empty (@evanceit)
- Fix doc for addImportPath, should also accept callable as input (@nguyenk)
- Change Base64 VLQ encoder/decoder implementation
- Generate inline sourcemap in command-line (@dexxa)
- Fix backslash escape (@bastianjoel)