title: How to get a label bold in open layers 3?
body: <p>I'm labelling markers in a vector layer.</p>
  
  <p>TextOptions of a ol.style.Text object include arrording to the docs (<a href="http://ol3js.org/en/v3.0.0-beta.1/apidoc/ol.style.html#TextOptions" rel="noreferrer">http://ol3js.org/en/v3.0.0-beta.1/apidoc/ol.style.html#TextOptions</a>) no option to change font-weight.</p>
  
  <p>In ol2 I used:</p>
  
  <pre><code>fontWeight: "bold"
  </code></pre>
  
  <p>This doesn't seem to work in ol3.</p>
  
  <p>How can this be done?</p>