Real auto save enable function

[ChillarAnand]

In addition to asking users to enable real-auto-save, we need to provide real-auto-save-enable function which activates real-auto-save mode in all writable buffers.

[DivineDominion]

I was looking through open issues here, and this sounds like global-real-auto-save-mode to me. Would that make sense? Enable globally, then disable locally for particular modes?