Changes to dark theme

Things I have done to the dark theme:
- replaced ANSI codes for bold with ANSI codes for bright. no longer requires 'draw bold as bright'
- made dirs blue and left cyan for custom file types
- colored some other things

Things that need to be done if adopted:
- update other themes with these changes
- update documentation

I am not sure how widely supported the ANSI bright codes are. I have not run into any issues yet.