e621/926 next/prev post shortcut per kompoman32

Shortcuts for e621.net / e926.net

Navigate through search query or pools.

Left arrow - prev.
Right arrow - next.
If there is pool navigation - shift + right/left arrow to navigate.
If there is pool navigation and no search navigation - works with/without shift.

Shift + Up - go to last in pool.
Shift + Down - go to first in pool.
(works only with shift key to preserve scrolling)

- Adds checkbox to always shows original size image