Theme tweaks

- gridUnits is dynamic again, using FontMetrics now
- Add a page to display some sizing-relevant details, so we can debug
  dpi problems a bit better on Android

Signed-off-by: Sebastian Kügler <sebas@kde.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-mobile/main.qml

@@ -72,6 +72,13 @@ ApplicationWindow {
 				stackView.push(logWindow)
 			}
 		}
+
+		MenuItem {
+			text: "Theme Information"
+			onTriggered: {
+				stackView.push(themetest)
+			}
+		}
 	}
 
 	StackView {
@@ -201,6 +208,11 @@ ApplicationWindow {
 		visible: false
 	}
 
+	ThemeTest {
+		id: themetest
+		visible: false
+	}
+
 	Component.onCompleted: {
 		print("units.gridUnit is: " + units.gridUnit);
 	}