[Merge] lp:~gerboland/qtubuntu/rasterGLSurface into lp:qtubuntu

[Gerry Boland]

The proposal to merge lp:~gerboland/qtubuntu/rasterGLSurface into lp:qtubuntu has been updated.

Commit Message changed to:

Fix rendering of apps using QQuickWidget

Based on a branch by Daniel d'Andrada
- Advertise RasterGLSurface capability
- Implement proper offscreen rendering support using EGL pixel buffers.
- Don't create mir surfaces for Qt::Desktop QWindows. Proper implementation still pending
- Add BackingStore toImage method, fixes render of QQuick and Widget content

For more details, see:
https://code.launchpad.net/~gerboland/qtubuntu/rasterGLSurface/+merge/306915
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Your team Ubuntu Phablet Team is requested to review the proposed merge of lp:~gerboland/qtubuntu/rasterGLSurface into lp:qtubuntu.