[Vala] Libuv bindings

[pancake <pancake youterm com>]

As far as vala supports async and lambdas/closures how hard would be to have it as a backend (instead of 
posix, glib..) because afaik it replaces lot of functionalities from those libraries.

I read once there was plans to modularize the backends of vala as plugins, so supporting objc or c++ should 
be easier and more maintainable than forking the whole project.

Whats the status?