OSC 10, 11, 12 #2


This patch adds support for OSC 10, 11, and 12 in the way they are implemented in most other terminals (e.g libvte, kitty). Specifically it differs from osc1011_12 in that it treats the background and foreground colors as distinct from palette colours 01 and 07 in order to facilitate the use of theme setting scripts like theme.sh which expect these colours to be distinct.