Implement volume steps support
The base for this is this patch. I modified it to make it smaller and work with the current code.
Those changes add volume step key so users can change how much is volume increased or decreased in one step and implements this in code.
This has been requested multiple times from users and while the tiny volume steps when holding shift got closer to what was requested its still not it. Users should have the ability to change the volume steps as they wish.
Edited by Haxk20