Shortcuts plugin for 4.4

[Olivier Fourdan]

Olivier Fourdan wrote:

> But thanks for merging the tree. I'll try to take a look a the problem 
> you mention although that particular part was developped by JF, not me.

Unfortunately, the result is bit hacky, as it's just the original 
plugins put into the same window with a tab at the top... woops.

Things may be a bit more complex then, as the various common data and 
callbacks need to be merged instead of just duplicated as it is .

Cheers,
Olivier.