title: Exclude function (not an entire file) from JavaScript code coverage
body: <p>I'm creating some unit tests with Jasmine and the test runner I'm using is Karma.
  I'm also checking the code coverage of these test specs with the karma-coverage plugin. </p>
  
  <p>I was wondering if there's any way of excluding certain functions from the code coverage itself and also from the Karma report (Istanbul actually). 
  I'm thinking that if the first one is solved then so is the second. </p>
  
  <p>Pretty sure there's no obvious way of doing this, as I've looked in Istanbul as well (karma-coverage uses it) but maybe some of you run into this before. </p>