Merge pull request nemomobile#5 from adenexter/master

[nemo-qtmultimedia-plugins] Ensure new nodes have valid geometry.

Merge pull request nemomobile#3 from sletta/no-change-during-rendering

[nemo-qtmultimedia-plugins] Don't change state during rendering.

Merge pull request nemomobile#2 from adenexter/init

[nemo-qtmultimedia-plugins] Fix initialization of properties.

Merge pull request nemomobile#1 from adenexter/destruction-crash

[nemo-qtmultimedia-plugins] Fix crash on destruction during playback.

[nemo-qtmultimedia-plugins] Add a VideoOutput plugin for the gstreame…

…r NemoVideoTexture interface.