Terminal strip editor: remember the manufacturer filter of each strip

The manufacturer chosen to filter the terminals of the Width column is
stored in the data of the terminal strip (information "manufacturer" of
terminal_strip_data, written only when set), and selected again when the
strip is shown in the editor. Each strip keeps its own manufacturer.
Older versions ignore this information.

TerminalStripEditor::apply() now starts from the current data of the strip
instead of a new TerminalStripData: the uuid of the strip was replaced by
a new one at each apply, and the new information would have been lost.

sources/TerminalStrip/terminalstripdata.cpp

@@ -52,6 +52,9 @@ QDomElement TerminalStripData::toXml(QDomDocument &xml_document) const
 	if (!m_description.isEmpty()) {
 		info_elmt.appendChild(infoToXml(xml_document, QStringLiteral("description"), m_description));
 	}
+	if (!m_manufacturer.isEmpty()) {
+		info_elmt.appendChild(infoToXml(xml_document, QStringLiteral("manufacturer"), m_manufacturer));
+	}
 
 	return root_elmt;
 }
@@ -79,6 +82,7 @@ bool TerminalStripData::fromXml(const QDomElement &xml_element)
 		else if (name == QLatin1String("name"))        {m_name = value;}
 		else if (name == QLatin1String("comment"))     {m_comment = value;}
 		else if (name == QLatin1String("description")) {m_description = value;}
+		else if (name == QLatin1String("manufacturer")) {m_manufacturer = value;}
 	}
 
 	return true;
@@ -91,6 +95,7 @@ TerminalStripData &TerminalStripData::operator=(const TerminalStripData &other)
 	m_name = other.m_name;
 	m_comment = other.m_comment;
 	m_description = other.m_description;
+	m_manufacturer = other.m_manufacturer;
 	m_uuid = other.m_uuid;
 
 	return *this;