#414 'Toggle folding' action

[Publicly Displayed Name]

One action that can be used both to collapse and to uncollapse one fold at a time.

Like "Toggle Outlining Expansion" in MSVS ( http://msdn.microsoft.com/en-us/library/td6a5x4s\(VS.100).aspx )

When caret is on the line containing at least one fold, it (or one under the caret. else the first to the right of the caret, else the first to the left of the caret) should be uncollapsed, otherwise the nearest enclosing fold should be collapsed.

There is virtually no reason to have two separate actions for folding and unfolding, while keyboards contain a limited number of keys! Also, it would be nice to have it bound by default somewhere on the left side of the keyboard, like Ctrl+E or nearby: thus one can fold/unfold stuff with his left hand without taking the right hand off the movement keys.