Timeline: Reset selection on clear() and emit rangeChanged() only once
Timeline: Reset selection on clear() and emit rangeChanged() only once

Change-Id: Ia4ca2fa6fac874ac66837e5c9d807a4e89b3b40e
Reviewed-by: Joerg Bornemann <47777b9406dbddd02a3fdca8341789a013805a11@theqtcompany.com>

xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,martyone/sailfish-qtcreator,xianian/qt-creator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator,martyone/sailfish-qtcreator,xianian/qt-creator