Terminfo: 24-Bit/3-byte Color Support

[Rüdiger Sonderfeld]

Hello,

it seems that some terminals now support for 24-bit RGB color values.  It seem 
to have started with KDE's Konsole[1].  But iTerm.app is adding support in the 
next release as well[2].  Terminfo should provide a way to support 24-bit RGB 
colors.

As far as I see it, the best approach would be to add new variable `setrgbf' 
and `setrgbb'.  And potentially CMY/CMYK versions.

E.g., the entries could look like

 konsole+24bit|KDE console 24bit/3byte RGB color feature,
    colors#16777216,
    setrgbf=\E[38;2;#1%d;#2%d;#3%dm,
    setrgbb=\E[48;2;#1%d;#2%d;#3%dm,
    use=xterm+256color,

  konsole-24bit|KDE console with 24bit/3byte RGB color support,
    use=konsole+256color, use=konsole+24bit,

  iTerm.app-24bit|iTerm.app with 24bit/3byte RGB color support,
    use=iTerm.app, usekonsole+24bit,

[1] 
https://projects.kde.org/projects/kde/applications/konsole/repository/revisions/master/raw/doc/user/README.moreColors
[2] https://code.google.com/p/iterm2/issues/detail?id=218

Regards,
Rüdiger