Initial work for index navigation improvements.
Make index page refreshing work.
Build missing [Reply] button.
Add all-pages index navigation. Close #1133
Hide the page list in non-paged mode.
Disable next/previous page keybinds in non-paged mode.
Use a sub-entry instead of a <select> for the index mode switcher.
Fix thread watcher/expansion/hiding buttons after an index refresh.
Fix threads highlighted by the filter not being put on top.
After an index refresh, only scroll down if needed.
Fix thread hiding after an index refresh.
Add index refresh shortcut in the header bar.
Also fix lazy/lame implementation of Header.addShortcut()
Dereference dead threads.
I wonder if this will be enough...
Reduce Index.sort() to 1 loop.
Regenerate the QR threads list correctly after an index refresh.
Only listen to 'IndexRefresh' events when browsing the index.
Take into account dead threads in the watcher after an index refresh.
Slightly better consistency between "reload"/"refresh"/"update" usage.
Add sorting options by bump order and creation date.
Refactor index generation/sorting.