* Unified preview-tui and preview-kitty
* Remove preview-kitty
* No need to set $TERMINAL
* fix undeclared variable
* Integrated support for scope.sh
* Review fixes
* allow_remote_control must be enabled on kitty
* Documentation, kitty splits and images fallback
* fix restoring kitty layout
* preview-tui: simplify, add generic fifo_pager()
I've commented new filetype checks for now, as we need to discuss which ones
should be included by default, keeping in mind that this is supposed to be a
minimal, adaptable plugin.
* preview-tui: preview with man, tar, unzip by default