Output directory not being used per reporter

[JoshSchreuder]

The example:

coverageReporter: {
  reporters:[
    {type: 'html', dir:'somedir/'},
    {type: 'teamcity'},
    {type: 'text-summary'}
  ],
}

Does not output html to somedir/, I think because of https://github.com/karma-runner/karma-coverage/blob/master/lib/reporter.js#L44 which only takes into account the directory of the coverageReporter object.

So if you specify as follows:

coverageReporter: {
  dir:'somedir/',
  reporters:[
    {type: 'html'},
    {type: 'teamcity'},
    {type: 'text-summary'}
  ],
}

HTML will be output to somedir/. Of course, this means that you can't have different directories for each reporter, so I think this is a bug.