Replaced deprecated xml attribute.

src/main/res/layout/activity_main.xml

@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:id="@+id/drawer_layout"
     android:layout_width="match_parent"
     android:layout_height="match_parent">
@@ -18,7 +17,7 @@
             android:layout_height="wrap_content"
             android:background="?colorPrimary"
             android:elevation="@dimen/toolbar_elevation"
-            app:theme="@style/ThemeOverlay.Syncthing.Toolbar" />
+            android:theme="@style/ThemeOverlay.Syncthing.Toolbar" />
 
         <android.support.v4.view.ViewPager
             android:id="@+id/pager"

src/main/res/layout/dialog_loading.xml

@@ -1,11 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:layout_width="wrap_content"
     android:layout_height="wrap_content"
     android:padding="@dimen/abc_action_bar_content_inset_material"
     android:gravity="center"
-    app:theme="?alertDialogTheme">
+    android:theme="?alertDialogTheme">
 
     <ProgressBar
         android:id="@+id/progress"

src/main/res/layout/dialog_usage_reporting.xml

@@ -1,11 +1,10 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:orientation="vertical"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:padding="10dip"
-    app:theme="?alertDialogTheme">
+    android:theme="?alertDialogTheme">
 
     <TextView
         android:layout_width="wrap_content"

src/main/res/layout/widget_toolbar.xml

@@ -9,5 +9,5 @@
     android:background="?colorPrimary"
     android:elevation="@dimen/toolbar_elevation"
     app:titleMarginStart="16dp"
-    app:theme="@style/ThemeOverlay.Syncthing.Toolbar"
-    app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
+    android:theme="@style/ThemeOverlay.Syncthing.Toolbar"
+    android:popupTheme="@style/ThemeOverlay.AppCompat.Light" />