title: Customize AppVeyor's version
body: <p>I'd like to be able to specify a custom version pattern for AppVeyor's build like this:</p>
  
  <pre><code>version: 1.0.{build}-{branch}
  </code></pre>
  
  <p>Though there're two additional rules:</p>
  
  <ol>
  <li>If a branch is master, I'd like to keep just 1.0.{build} skipping on the branch part</li>
  <li>If a branch is named like features/something, I'd like to get 1.0.{build}-something in result</li>
  </ol>
  
  <p>Is there any place in AppVeyor's pipleline where I could place those customisations?</p>