So this is a little self serving, but I think we should consider dropping support for IE9.  The data is interesting.  I'm seeing a [0.6% browser market share for IE9](https://netmarketshare.com/browser-market-share.aspx?options=%7B%22filter%22%3A%7B%22%24and%22%3A%5B%7B%22deviceType%22%3A%7B%22%24in%22%3A%5B%22Desktop%2Flaptop%22%5D%7D%7D%5D%7D%2C%22dateLabel%22%3A%22Trend%22%2C%22attributes%22%3A%22share%22%2C%22group%22%3A%22browserVersion%22%2C%22sort%22%3A%7B%22share%22%3A-1%7D%2C%22id%22%3A%22browsersDesktopVersions%22%2C%22dateInterval%22%3A%22Monthly%22%2C%22dateStart%22%3A%222017-07%22%2C%22dateEnd%22%3A%222018-06%22%2C%22segments%22%3A%22-1000%22%2C%22pageLength%22%3A50%7D).

What's neat about that data is that IE8 has twice the usage of IE9 🤷‍♂️ And IE10 has only 0.54% market share!  I could make a reasonable argument for dropping both IE9 *and* IE10.  

Of course, I'm only looking at this because I'd very much like to ship a new npm module with a few recently merged changes, and the IE9 tests are failing :)  

What are folks thoughts?  Does anyone feel strongly about the IE support matrix as it stands today?

@nickuraltsev @mzabriskie 
karma.conf.js
if (runAll || process.env.SAUCE_EDGE) {
      customLaunchers.SL_Edge = createCustomLauncher('microsoftedge', null, 'Windows 10');
    }
    
    if (runAll || process.env.SAUCE_IOS) {
      
      
      
      
      
    }
    
    if (runAll || process.env.SAUCE_ANDROID) {
      
      
      
    }
    browsers = Object.keys(customLaunchers);
  } else if (process.env.TRAVIS_PULL_REQUEST && process.env.TRAVIS_PULL_REQUEST !== 'false') {
    console.log(
      'Cannot run on Sauce Labs as encrypted environment variables are not available to PRs. ' +
      'Running on Travis.'
    );
    browsers = ['Firefox'];
  } else {
    console.log('Running locally since SAUCE_USERNAME and SAUCE_ACCESS_KEY environment variables are not set.');
    browsers = ['Firefox', 'Chrome', 'Safari', 'Opera'];
  }
  config.set({