Fix path handling under Windows

**commit 4c7716c**

Some tests failed under the windows operating system, because the comparison of

> actual: {{outlet}}**\r\n**
> expected: {{outlet}}**\n**

failed. This can be fixed by using the ```os.EOL``` constant.

--------

**commit 7319849**

Karma seems to pass file paths to its preprocessors using forward slashes regardless of the current operating system. When I use 

    files: [
      ....
      'templates/*.handlebars'
      ....
    ],

in my karma.conf.js under Windows, karma-ember-preprocessor receives the path E:/.../.../templates/application.handlebars. During processing it tries to split the path by ```path.sep + '/templates/' + path.sep```. This fails because the Regex does not match.

The proposed change fixes this problem, since it first normalizes the path and then processes it.