Parser misbehaves on complex control code sequences

[aaron-em]

In this sequence:

They ^Bdon't ^]need ^_to ^]be ^C03opened ^Band ^]closed ^Bin ^]lifo ^C04order

the following style and color changes occur:

1. Start bold - bold
2. Start italic - bold, italic
3. Start underline - bold, italic, underline
4. End italic - bold, underline
5. Start color (green foreground) - bold, underline, green
6. End bold - underline, green
7. Start italic - italic, underline, green
8. Start bold - bold, italic, underline, green
9. End italic - bold, underline, green
10. Start color (red foreground, implicitly ending the green from 5 above) - bold, underline, red
11. Implicitly end all styles at EOL

Whatever IRC client clsr uses renders this sequence thus:

that is, correctly, whereas rcirc-styles renders it thus:

which is clearly bogus - the color replacement is the only part that works; the changes of style aren't rendered at all.