MATE Desktop 1.16 will land in Ubuntu MATE 16.10

[maximuscore]

@Wimpy

This will not only make Ubuntu MATE 16.10 the first distro to feature a full GTK3+ implementation of MATE but also the first to ship MATE Desktop 1.16

Can we expect some sort of backport to 16.04, even if it's just built with GTK2 again?