fix: use output dir per reporter

Closes #42
Merge pull request #43 from kombucha/issue-#42-output-directory

FIXED issue #42 - Output directory not being used per reporter
feat: update istanbul

See https://github.com/gotwarlost/istanbul/issues/15
feat: revert update istanbul

Because it breaks coverage with CoffeeScript (ibrik).

This reverts commit b696c3e325053bb093b970934391497b99d01248.
chore: release v0.1.5
feat: no longer write json unless configured

BREAKING CHANGE: No json coverage is generated by default. If you want that, please use `json` reporter:

```js
coverageReporter: {
  type: 'json'
}

// or with multiple reporters
coverageReporter: {
  reporters: [
    {type: 'html', dir: 'coverage'},
    {type: 'json', dir: 'coverage'},
  ]
}
```
chore: release v0.2.0
feat: update istanbul to 0.2.3, ibrik to 1.1.1
docs(readme): fix a typo
Merge pull request #67 from taylorhakes/master

feat: update istanbul to 0.2.3, ibrik to 1.1.1
test(deps): update karma
docs(readme) add CoffeeScript example
chore: release v0.2.1
feat: Adding baseline JavaScript coverage switch

Add the ability to include baseline JavaScript code coverage.

Closes #11
remove unnecessary tab
move instrumenter instantiation back into createCoveragePreprocessor, fix tests