title: TextView inside ConstraintLayout clips text and layout_margin cant not be shown correctly
body: <p>I use : 
  compile 'com.android.support.constraint:constraint-layout:1.0.2'</p>
  
  <p>The main problems are：</p>
  
  <ol>
  <li>layout_margin can't be shown correctly;</li>
  <li>child textview's text is clipped.</li>
  </ol>
  
  <p>Details as below:</p>
  
  <p>This is my xml:</p>
  
  <pre><code>&lt;android.support.constraint.ConstraintLayout
      xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:app="http://schemas.android.com/apk/res-auto"
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:background="@android:color/darker_gray"
      android:padding="8dp"&gt;
  
      &lt;ImageView
          android:id="@+id/reviewer_avatar"
          android:layout_width="48dp"
          android:layout_height="48dp"
          android:background="@color/colorAccent"
          android:contentDescription="@string/avatar"
          android:layout_margin="8dp"
          app:layout_constraintLeft_toLeftOf="parent"
          app:layout_constraintTop_toTopOf="parent"/&gt;
  
      &lt;TextView
          android:id="@+id/reviewer_name"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="@string/reviewer_name"
          android:textSize="16sp"
          app:layout_constraintBottom_toTopOf="@+id/comment_floor"
          app:layout_constraintLeft_toRightOf="@+id/reviewer_avatar"
          app:layout_constraintTop_toTopOf="@+id/reviewer_avatar"
          app:layout_constraintVertical_chainStyle="packed"/&gt;
  
      &lt;TextView
          android:id="@+id/comment_floor"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="@string/reviewer_floor_text"
          android:textSize="12sp"
          app:layout_constraintBottom_toBottomOf="@+id/reviewer_avatar"
          app:layout_constraintLeft_toRightOf="@+id/reviewer_avatar"
          app:layout_constraintTop_toBottomOf="@+id/reviewer_name"/&gt;
  
      &lt;TextView
          android:id="@+id/comment_period"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_marginLeft="6dp"
          android:text="@string/comment_period_text"
          android:textSize="12sp"
          app:layout_constraintLeft_toRightOf="@+id/comment_floor"
          app:layout_constraintTop_toBottomOf="@+id/reviewer_name"/&gt;
  
      &lt;TextView
          android:id="@+id/comment_content"
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="@string/large_text"
          android:textSize="16sp"
          app:layout_constraintLeft_toRightOf="@+id/reviewer_avatar"
          app:layout_constraintTop_toBottomOf="@+id/reviewer_avatar"/&gt;
  &lt;/android.support.constraint.ConstraintLayout&gt;
  </code></pre>
  
  <p>This is my screenshot:</p>
  
  <p><a href="https://i.stack.imgur.com/QtHw6.jpg" rel="noreferrer"><img src="https://i.stack.imgur.com/QtHw6.jpg" alt="This is my screenshot"></a></p>