title: Position a view in relation to another view using RMQ
body: <p>I begin today to use RMQ for my RubyMotion project.
  I read the documentation of the frame / grid system but I cannot find a way to position a view related to another view.</p>
  
  <p>I have 4 UIbuttons with an image inside. I want to place a UILabel under every button centered aligned. </p>
  
  <p>I'm not using grid, i place my button with frame:</p>
  
  <pre><code>  def quiz_button(st)
      st.background_color = color.white
      st.frame = {l: 40, t: 160, w: 120, h: 120}
      st.image_normal = image.resource('sailboat')
      st.image_selected = image.resource('sailboat_selected')
    end
  </code></pre>
  
  <p>In MotionKit I have <code>"frame below(:username_input, down: 8)"</code>so I can place a view under a specific view, in RMQ I cannot find something that help me to do the same.</p>