add - sort threads in timeline tab by start time

Now it sorts threads as in picture: 
![2014-10-17_1957](https://cloud.githubusercontent.com/assets/1964214/4681805/4b9d2144-5616-11e4-9adb-3f26bc60b3a1.png)

It seems that we should go back to previous view of timeline (but with hostnames separating feature)

`timeline.json` can be found on Gist: https://gist.github.com/lanwen/8142a8ef770e31b6cd6e