Additional Terminal Support

[AlexAtkinson]

Please add support for the following terminal emulators. They support SIXEL.
https://www.arewesixelyet.com

• Konsole
• Yakuake : Uses Konsole
• Contour

Thanks

[tclift]

It appears that Yakuake and Konsole are not supported because in response to "send device attributes" they send:

$ echo -e "\e[c"

^[[?62;1;4c

(Konsole source), where jplot expects 4 (not 4c) here (jqplot source).

If I change:

if len(t) == 1 && t[0] == '4' {

to:

if t[0] == '4' {

then indeed, jplot starts working in Yakuake.

Looking at the xterm docs on Sixel as a reference, I don't know what the significance of 4c is (vs 4). Was the len(t) == 1 added for a specific reason/fix? If not, maybe it can be removed.