Implement gravity options and ui (#117)

src/res/qml/motion_page/MotionPage.qml

@@ -3,9 +3,10 @@ import QtQuick.Controls 2.0
 import QtQuick.Layouts 1.3
 import ovras.advsettings 1.0
 import "../common"
-import "universe_drag"
-import "universe_turn"
+import "space_drag"
+import "space_turn"
 import "height_toggle"
+import "gravity"
 
 MyStackViewPage {
     headerText: "Motion Settings"
@@ -13,12 +14,14 @@ MyStackViewPage {
     content: ColumnLayout {
         spacing: 18
 
-        UniverseDragGroupBox { id: universeDragGroupBox }
+        SpaceDragGroupBox { id: spaceDragGroupBox }
 
-        UniverseTurnGroupBox { id: universeTurnGroupBox }
+        SpaceTurnGroupBox { id: spaceTurnGroupBox }
 
         HeightToggleGroupBox { id: heightToggleGroupBox }
 
+        GravityGroupBox { id: gravityGroupBox }
+
         Item {
             Layout.fillHeight: true
         }