Increase map real estate when defining offline maps.

src/QtLocationPlugin/QGCMapEngine.cpp

@@ -266,7 +266,7 @@ QGCTileSet
 QGCMapEngine::getTileCount(int zoom, double topleftLon, double topleftLat, double bottomRightLon, double bottomRightLat, UrlFactory::MapType mapType)
 {
     if(zoom <  1) zoom = 1;
-    if(zoom > 18) zoom = 18;
+    if(zoom > MAX_MAP_ZOOM) zoom = MAX_MAP_ZOOM;
     QGCTileSet set;
     set.tileX0 = long2tileX(topleftLon,     zoom);
     set.tileY0 = lat2tileY(topleftLat,      zoom);

src/ui/MainWindowLeftPanel.qml

@@ -282,6 +282,7 @@ Item {
 
     //-- Main Setting Display Area
     Rectangle {
+        id:             settingDisplayArea
         anchors.left:   __verticalSeparator.right
         width:          mainWindow.width - __leftMenu.width - __verticalSeparator.width
         height:         parent.height - toolBar.height - __topSeparator.height