Add tools context to activities

app/src/main/res/layout/activity_main.xml

 <android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
-  xmlns:tools="http://schemas.android.com/tools"
   android:id="@+id/drawer_layout"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
-  android:fitsSystemWindows="true"
-  tools:openDrawer="start">
+  android:fitsSystemWindows="true">
 
   <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:app="http://schemas.android.com/apk/res-auto"

app/src/main/res/layout/content_chatlist.xml

 <de.kuschku.quasseldroid_ng.util.ui.NavigationDrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"
   xmlns:app="http://schemas.android.com/apk/res-auto"
+  xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:layout_gravity="start"
   android:background="?android:attr/windowBackground"
   android:fitsSystemWindows="true"
-  app:insetForeground="?attr/colorPrimaryDark">
+  app:insetForeground="?attr/colorPrimaryDark"
+  tools:showIn="@layout/activity_main">
 
   <LinearLayout
     android:layout_width="match_parent"

app/src/main/res/layout/content_main.xml

 <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:tools="http://schemas.android.com/tools"
   android:layout_width="match_parent"
-  android:layout_height="match_parent">
+  android:layout_height="match_parent"
+  tools:showIn="@layout/activity_main">
 
   <LinearLayout
     android:layout_width="match_parent"

app/src/main/res/layout/content_nicklist.xml

 <de.kuschku.quasseldroid_ng.util.ui.DrawerRecyclerView xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:tools="http://schemas.android.com/tools"
   android:id="@+id/nickList"
   android:layout_width="match_parent"
   android:layout_height="match_parent"
   android:layout_gravity="end"
   android:background="?android:attr/windowBackground"
   android:clipToPadding="false"
-  android:fitsSystemWindows="true" />
+  android:fitsSystemWindows="true"
+  tools:showIn="@layout/activity_main" />