#729 Previous audio track and subtitle hotkeys

[Vitaly]

It is a common situation for people studying foreign languages when there are 5 or even more audio and subtitle tracks for one video file (e. g. several languages, or several translation versions). Very often we have to switch temporarily to next track (e. g. to see translation variant for a particular phrase) and quickly turn back. There are "next audio" and "next subtitle" shortcuts in SMPlayer, but no "previous audio/subtitle". Can not believe such an advanced player lacks this simple ability, but that is so! One have to switch through all of the tracks in circle like 2->3->4->5->1 to get back (while playing!) which is VERY annoying.
Very wanted an ability to assign keyboard shortcut to "previous subtitle" and "previous audio" actions as opposite to "next" ones, like in Media Player Classic and other players.

Also please pay you attention to feature request #77 which seems to be abandoned for a decade, though it is very common and useful and implemented in almost any other player. There was a workaround suggested in forum, but it is not so useful. Seems like these feature requests are similar and simple and can be implemented simultaneously.

[Ricardo Villalba]

Actions for previous audio/subtitle have been added in svn r9199.