Add support for Ezoom (or a similar zoom functionality)

Ok, this is more like a feature request:

I always used the Ezoom plugin with compiz, I find it useful when I have to show something to people that are slightly distant, or I have to lend my laptop to people with slight sight impairment

I tried to enable the Zoom feature in Universal Access (and to activate the shortcut) but it seems non functional

the Ezoom plugin got a slight performance regression in a previous version of unity, but now is working quite fine, except that the launcher isn't resized with the rest of the desktop (but this is fine, as long as I want to show something else)

but now the situation may degrade: the new shortcuts overlay is shown when zooming (to zoom in I use Super+scroll up, and Super+scroll down to zoom out), and when releasing the Dash is shown...

on top of this: I've been able to activate this plugin thanks to ccsm, but since ccsm is being deprecated, I think that unity may be better off by having an offically supported zoom functionality (with options in the control-center and official bindings/shortcuts)