Add navigation toolbar (#1)

* Add preferences view skeleton

* Add toolbar & help button

* Add working back button

* Title of page in toolbar

* Remove unused imports

* Make comments better!

* Remove unused drawer element

* Remove superfluous > 1 check

* Use point size font instead of pixel size

* Add AppView page title

app/gui/PcView.qml

@@ -17,6 +17,7 @@ GridView {
     anchors.bottomMargin: 5
     cellWidth: 350; cellHeight: 350;
     focus: true
+    objectName: "Computers"
 
     Component.onCompleted: {
         // Start polling when this view is shown
@@ -135,6 +136,7 @@ GridView {
                         var component = Qt.createComponent("AppView.qml")
                         var appView = component.createObject(stackView)
                         appView.computerIndex = index
+                        appView.objectName = "Apps on " + model.name
                         stackView.push(appView)
                     }
                     else {