Follow project coding style. Issue #2192.
Images cache control code edit
Follow project coding style. Issue #2192.
Add higest and lowest priority icons into toolbar
Hide priority menu items when queueing is disabled
Follow project coding style. Issue #2192.
Update torrent list after operations with torrents.

Immediately update torrent list after some operations with torrents.
Such as changing priority, adding torrent, pause/resume, etc.
Save torrent list sort order in local storage
Restore selected filter on page load
Follow project coding style. Issue #2192.
Add sequential downloading menu items
Dynamically show 'Start' and 'Pause' menu items
Add space before priority menu item
Merge pull request #2254 from buinsky/master

WebUI: Some changes