Fallback to loading theme icons from resources

Since not all platforms support theme icons, we need to pack
them into resources and fallback to that resource theme.

There seems to be a bug in Qt
(https://bugreports.qt-project.org/browse/QTBUG-16697), thus
default theme name (hicolor) does not work. So we test for
'window-close' theme icon on startup and if not found, set theme
name to 'subsurface'

Signed-off-by: Sergey Starosek <sergey.starosek@gmail.com>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

icons/subsurface/index.theme

@@ -0,0 +1,7 @@
+[Icon Theme]
+Name=Subsurface
+Comment=Subsurface fallback theme
+Directories=32x32/actions
+
+[32x32/actions]
+Size=32

qt-ui/mainwindow.cpp

@@ -70,6 +70,9 @@ MainWindow::MainWindow() : QMainWindow(),
 	m_Instance = this;
 	ui.setupUi(this);
 	setWindowIcon(QIcon(":subsurface-icon"));
+	if (!QIcon::hasThemeIcon("window-close")) {
+		QIcon::setThemeName("subsurface");
+	}
 	connect(ui.ListWidget, SIGNAL(currentDiveChanged(int)), this, SLOT(current_dive_changed(int)));
 	connect(PreferencesDialog::instance(), SIGNAL(settingsChanged()), this, SLOT(readSettings()));
 	connect(PreferencesDialog::instance(), SIGNAL(settingsChanged()), ui.ListWidget, SLOT(update()));

qt-ui/usermanual.ui

@@ -74,7 +74,7 @@
           <string/>
          </property>
          <property name="icon">
-          <iconset theme="go-previous">
+          <iconset theme="go-up">
            <normaloff/>
           </iconset>
          </property>
@@ -98,7 +98,7 @@
           <string/>
          </property>
          <property name="icon">
-          <iconset theme="go-next">
+          <iconset theme="go-down">
            <normaloff/>
           </iconset>
          </property>

subsurface.qrc

@@ -53,6 +53,10 @@
         <file alias="icon_ceiling_dc">icons/pc.png</file>
         <file alias="icon_ead">icons/ead.png</file>
         <file alias="icon_HR">icons/icon-HR.png</file>
-	<file alias="calendar">icons/calendarbg.png</file>
+        <file alias="calendar">icons/calendarbg.png</file>
+        <file>icons/subsurface/index.theme</file>
+        <file>icons/subsurface/32x32/actions/go-down.png</file>
+        <file>icons/subsurface/32x32/actions/go-up.png</file>
+        <file>icons/subsurface/32x32/actions/window-close.png</file>
     </qresource>
 </RCC>