QmlDesigner: Remove unneeded qualifications

Mostly done using the following ruby script:
Dir.glob('**/*.cpp').each { |file|
  next if file =~ %r{src/shared/qbs|/qmljs/}
  s = File.read(file)
  s.scan(/^using namespace (.*);$/) {
    ns = $1
    t = s.gsub(/^(.*)\b#{ns}::((?!Const)[A-Z])/) { |m|
      before = $1
      char = $2
      if before =~ /"|\/\/|\\|using|SIGNAL|SLOT|Q_/
        m
      else
        before + char
      end
    }
    if t != s
      puts file
      File.open(file, 'w').write(t)
    end
  }
}

Change-Id: I492792bb9e5655c55795e938031efc557c9a462f
Reviewed-by: Thomas Hartmann <Thomas.Hartmann@digia.com>

src/plugins/qmljseditor/qmljsquickfix.cpp

@@ -57,7 +57,7 @@ QmlJSQuickFixOperation::QmlJSQuickFixOperation(const QmlJSQuickFixInterface &int
 
 void QmlJSQuickFixOperation::perform()
 {
-    QmlJSRefactoringChanges refactoring(QmlJS::ModelManagerInterface::instance(),
+    QmlJSRefactoringChanges refactoring(ModelManagerInterface::instance(),
                                         m_interface->semanticInfo().snapshot);
     QmlJSRefactoringFilePtr current = refactoring.file(fileName());