Feature: Ability to toggle subtitles with shortcut

[svr333]

Description

Allow the subtitles to be toggled by pressing a key (I'd suggest C, similar to YouTube's player for example). This would just be a main toggle to toggle subtitles on/off.

There's already a toggle to change subtitle's size/delay, but not one to toggle subtitles in general.

[kKaskak]

There is a shortcut to open the subtitles' menu easily with "s" key on your keyboard. The easiest way to disable subtitles in a flash it to click "s" followed by ↓ and enter (↵) and again press "s" (to hide the subtitles settings pop-up)