Since the Qt upgrade, Plasma Mobile boots into a black screen, even
on the current version in the master branch. Bhushan recommended we
update to the latest plasma framework anyway (which is possible now
due to the newer Qt version) and try to fix it from there. See #159.
[skip ci].
Also includes a revert for the commit which broke the libinput devices
for consolekit session. I am still unsure of solution for both of the
problems to suggest upstream. But it is in my todo list.
Fixes#1585
