Fix for highlight-3.13 compatibility

- No more override
- No x86 build
Filename in QuickLook title
Handle QuickLook for public.data files ...

... which usually lack file extensions, e.g., Makefile, README, etc.
(inspired by QLStephen[1]).  We might need to adapt the
whitelist/blacklist approach used in QLStephen.

[1]: https://github.com/whomwah/qlstephen
Cleaned up colorize.sh

- zsh -> bash
- intuitive handling of special cases
- clearer flow of fallback to plain text