Merge pull request #6 from sletta/mer-stable

[qtwayland] Avoid virtual calls in constructors.
Reduce headers inter-dependency in the QPA plugin

Change-Id: I8b810e54531453b6a80250555c21bb0b1e6e76cc
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>
Merge pull request #7 from giucam/headers

Reduce headers inter-dependency in the QPA plugin
MER: Remove old V8 requirement.

Change-Id: I9e6bcf56354278b3192d22a7b04fc696a5955f65
Avoid crashing race condition.

Change-Id: I940bcbc509a689804a02f71af45f5efc19bccf9f
Reviewed-by: Giulio Camuffo <giulio.camuffo@jollamobile.com>