fix(plug-in): use minimatch to compare patterns 

When figuring out where to insert the built
bundle file, karma-bro would exactly compare the
patterns from config.preprocessors against those
in config.files (using indexOf). This behaves 
incorrectly when a more general glob pattern is 
specified in the preprocessor.

This commit fixes this by using minimatch 
to compare globs when figuring out where to insert
the bundle.

For example, given the following config: 

```javascript
config.set({
  preprocessors: {
    ‘test/*.js’: [‘browserify’]
  },

  files: [
    ‘vendor/external.js’,
    ‘test/*Spec.js’
  ]
});
```

karma-bro will now insert the bundle in between
the two files specified, because while
`test/*Spec.js === test/*.js` returns `false`, 
`minimatch(‘test/*Spec.js’, ‘test/*.js’)` returns
`true`.