Wayland and Mir enabled

Okay, now that 2.0.2 has shipped, Wayland and Mir support are back to
enabled by default, in the configure and CMake scripts.

Please let us know if this causes problems, as you might have a chunk of
code that wasn’t compiled on your Linux box as late as 2.0.2, and we’d
like to stabilize these targets before 2.0.3.