Core: 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: I5c6690f51488bf8ca3610ba9fb11e6e5fd814aaa
Reviewed-by: Christian Kandeler <christian.kandeler@theqtcompany.com>
Reviewed-by: hjk <hjk@theqtcompany.com>

src/plugins/coreplugin/messagemanager.cpp

@@ -47,7 +47,7 @@ MessageManager::MessageManager()
 {
     m_instance = this;
     m_messageOutputWindow = 0;
-    qRegisterMetaType<Core::MessageManager::PrintToOutputPaneFlags>();
+    qRegisterMetaType<MessageManager::PrintToOutputPaneFlags>();
 }
 
 MessageManager::~MessageManager()