use app namespace instead of android

Signed-off-by: Andy Scherzinger <info@andy-scherzinger.de>

scripts/analysis/findbugs-results.txt

@@ -1 +1 @@
-382
+381

scripts/analysis/lint-results.txt

@@ -1,2 +1,2 @@
 DO NOT TOUCH; GENERATED BY DRONE
-      <span class="mdl-layout-title">Lint Report: 76 warnings</span>
+      <span class="mdl-layout-title">Lint Report: 92 warnings</span>

src/main/res/layout/file_list_actions_bottom_sheet_fragment.xml

@@ -17,11 +17,12 @@
   License along with this program.  If not, see <http://www.gnu.org/licenses/>.
 -->
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-              xmlns:tools="http://schemas.android.com/tools"
-              android:layout_width="match_parent"
-              android:layout_height="wrap_content"
-              android:orientation="vertical"
-              android:background="@color/bg_default">
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="wrap_content"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    android:orientation="vertical"
+    android:background="@color/bg_default">
 
     <TextView
         android:id="@+id/add_to_cloud"
@@ -49,7 +50,7 @@
             android:layout_height="wrap_content"
             android:contentDescription="@null"
             android:src="@drawable/ic_action_upload"
-            android:tint="@color/primary"/>
+            app:tint="@color/primary"/>
 
         <TextView
             android:layout_width="wrap_content"
@@ -80,7 +81,7 @@
             android:layout_height="wrap_content"
             android:contentDescription="@null"
             android:src="@drawable/ic_import"
-            android:tint="@color/primary"/>
+            app:tint="@color/primary"/>
 
         <TextView
             android:layout_width="wrap_content"
@@ -111,7 +112,7 @@
             android:layout_height="wrap_content"
             android:contentDescription="@null"
             android:src="@drawable/ic_camera"
-            android:tint="@color/primary" />
+            app:tint="@color/primary" />
 
         <TextView
             android:layout_width="wrap_content"
@@ -152,7 +153,7 @@
             android:layout_height="wrap_content"
             android:contentDescription="@null"
             android:src="@drawable/ic_action_create_dir"
-            android:tint="@color/primary"/>
+            app:tint="@color/primary"/>
 
         <TextView
             android:layout_width="wrap_content"
@@ -321,7 +322,7 @@
             android:layout_height="wrap_content"
             android:contentDescription="@null"
             android:src="@drawable/ic_post_add"
-            android:tint="@color/primary" />
+            app:tint="@color/primary" />
 
         <TextView
             android:layout_width="wrap_content"