Support for OSC escape sequences 10, 11 and 12 to modify the bg, fg and
cursor colors. I selected entries in the colorname table after the 255
position for defaultfg, defaultbg and defaultcs
Scroll is a program that stores all the lines of its child and be used in st as
a way of implementing scrollback.
This solution is much better than implementing the scrollback in st itself
because having a different program allows to use it in any other program
without doing modifications to those programs.
