[Core] Better tabbar size hint calculation.
[LMP] Refactored artists buttons to StdArtistActions for #1437.
[LMP] SysIconProvider -> ThemeImageProvider in SimilarView.
[LMP] SysIconProvider -> ThemeImageProvider in HypesWidget.
[LMP] SysIconProvider -> ThemeImageProvider in ReleasesWidget.
[LMP] Removed SysIconsProvider.

Util::ThemeImageProvider is a way to go.
[LMP] Provide sysIcons for BioView for #1437.
[LMP] Proper icon for audio preview.
[LMP] Refactored artist actions handling for #1437.
[LMP] Add std artist actions to bio view.

This finally closes #1437.
[GActs] Invoke previous event filter in bundled Qxt copy.

For #1442.
[Util] Use QAbstractEventDispatcher::setEventFilter() for #1442.

qt_installX11EventFilter() is removed in Qt 5.
[KBSwitch] Use QAbstractEventDispatcher::setEventFilter() for #1442.

qt_installX11EventFilter() is removed in Qt 5.
[MT] Use QAbstractEventDispatcher::setEventFilter().

qt_installX11EventFilter() is removed in Qt 5.

This finally closes #1442.
[Core] Kludge for Oxygen style, fixes #1439.
Merge branch 'master' into qt5
[Kinotify] qt5-compatibility
[Core] add X11Extras module to dependencies
[Util] add X11Extras module to dependencies
[Lackman] qt5-compatibility