[Qgis-developer] Renaming QML to QSL

[Matthias Kuhn]

Developers,

We all know and appreciate .qml files. Some of us for shipping QGIS
styles some of us for writing QtQuick applications [1].

The second one become more important with Qt5 and so increase the risk
of confusing the two file types. We already have technical collisions of
the two file endings now [2]

To avoid this, I propose to rename .qml files to .qsl for QGIS 3.

Regards
Matthias

[1] https://en.wikipedia.org/wiki/QML
[2] https://github.com/qgis/QGIS/pull/3266