generic xterm support

[cp-on-github]

It would be nice to add generic xterm support, perhaps via xterm control sequences (xfree86.org). See below for a mock-up of this idea. This should cover many terminal programs that are currently not supported.

apply_xterm() {
  # |  
  # | Applying values on xterm
  # | ===========================================
  ESC="\e"
  CSI="${ESC}["
  OSC="${ESC}]"
  ST="${ESC}\\"

  echo "Patching xterm with new colors..."
  for idx in {0..15}; do
      COLOR=$(printf 'COLOR_%02d' $(expr $idx + 1 ))
      printf "${OSC}4;${idx};${!COLOR}${ST}"
      printf "${CSI}48;5;${idx}m${!COLOR}${CSI}0m"
    done 

    printf "${OSC}10;${FOREGROUND_COLOR}${ST}"
    printf "${OSC}11;${BACKGROUND_COLOR}${ST}"
    printf "${OSC}12;${CURSOR_COLOR}${ST}"
}