[3896] Nowy ekran - timeline.

https://gist.github.com/lukkolstx/4693138a2ace6d819ac4
Wrong style, it should be like this:

```javascript
$.getJSON("/api/v1/presence_start_end/"+selected_user, function(result) {

    // Converts timestamps to date format
```
There are many more style mistakes below, but i believe that You will change that part of code, so I won't comment them.

Please get familiar with [JavaSciprt style guide](https://github.com/airbnb/javascript)