Make context title and summary changeable (#329)

* Make context title and summary changeable

Closes #30

* Fix checkboxes on context settings page

So...I am new to Qt, and I forgot that checkboxes can have a label.
Duh. Fixed.

* Put context settings in a different place

* Put ReplaceMessage and ReplaceVariable in Utilities

src/settings/contextsettingspage.h

@@ -0,0 +1,75 @@
+/*
+ * Strawberry Music Player
+ * This file was part of Clementine.
+ * Copyright 2010, David Sansome <me@davidsansome.com>
+ * Copyright 2018-2019, Jonas Kvinge <jonas@jkvinge.net>
+ *
+ * Strawberry is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Strawberry is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Strawberry.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#ifndef CONTEXTSETTINGSPAGE_H
+#define CONTEXTSETTINGSPAGE_H
+
+#include "config.h"
+
+#include <stdbool.h>
+#include <QObject>
+#include <QString>
+#include <QAction>
+#include <QtEvents>
+#include <QCheckBox>
+#include <QLabel>
+
+#include "settingspage.h"
+
+class SettingsDialog;
+class Ui_ContextSettingsPage;
+
+class ContextSettingsPage : public SettingsPage
+{
+  Q_OBJECT
+
+public:
+  ContextSettingsPage(SettingsDialog *dialog);
+  ~ContextSettingsPage();
+
+  enum ContextSettingsOrder {
+    TECHNICAL_DATA,
+    ENGINE_AND_DEVICE,
+    ALBUMS_BY_ARTIST,
+    SONG_LYRICS,
+    NELEMS,
+  };
+
+  static const char *kSettingsGroup;
+  static const char *kSettingsTitleFmt;
+  static const char *kSettingsSummaryFmt;
+  static const char *kSettingsGroupLabels[ContextSettingsOrder::NELEMS];
+  static const char *kSettingsGroupEnable[ContextSettingsOrder::NELEMS];
+
+  void Load();
+  void Save();
+
+private slots:
+  void InsertVariableFirstLine(QAction *action);
+  void InsertVariableSecondLine(QAction *action);
+  void ShowMenuTooltip(QAction *action);
+
+private:
+  Ui_ContextSettingsPage *ui_;
+  QCheckBox *checkboxes[ContextSettingsOrder::NELEMS];
+};
+
+#endif // CONTEXTSETTINGSPAGE_H