Highlights design

Continuation of #257, just that it is a pull request against development branch. This pull request is addressing #256. Instead of each highlight being one big rectangle area, find smaller reasonable sections and draw border around only them.
The previous three lines can be made shorter with
```
temp = _.map segments, (segment) ->
  [_.clone(segment), true]
```

Just an idea, that you can usually find underscore functions that work on whole arrays etc.