preview-tui improvements (#869)

preview-tui improvements (#869)

* Update preview-tui

* trap SIGWINCH

* Update preview-tui

fix CircleCI test

* fix CircleCI...

* add pdf/epub

forgot to add pdf/epub when adpating my own working script to the upstream version

* add USE tests

* add office preview

allows preview of ods, odt, docx, pptx, etc

* remove resize trap, show static gif

Removed the faulty resize code and show static gif when USE_GIFPREVIEW is not set.

* loop gif playback

* refactor imagepreview

* scale kitty preview

* fix ueberzug_remove regression

* add optional atool support

* single depth, colorized tree preview

also empty pager prompt

* atool optional

* window resize working

* USE_UEBERZUG check

* conditional trap

I can't fully explain the behavior I'm seeing but this seems to work as its supposed to.

* adopt TMPDIR

* prevent extra readline after window resize

* shellcheck fix

* clear preview pane after resize

prevents (seemingly random) pager previews from showing after resize

* fix stray fifo from subshells

* add preview-tui-ext