Merge remote-tracking branch 'github/3.8'

Conflicts:
	org.eclipse.scout.rt.ui.rap.incubator.filechooser.feature/feature.xml
	org.eclipse.scout.rt.ui.rap.incubator.filechooser/META-INF/MANIFEST.MF
	org.eclipse.scout.rt.ui.rap.incubator.filechooser/src/org/eclipse/scout/rt/ui/rap/form/fields/filechooserfield/RwtScoutFileUploadField.java