Update waterfall view

New features:
- configurable variables
- lazy load builds (infinite scroll)
- stay on left Y (time) axis
- auto update fix (it should work now)
- visual distinction for the time ticks
- support running builds and unfinished steps
- cache steps
- clickable builder names
This will reload *all* data + some more, instead of loading more data, and appending it.

Need to improve the buildbotService so that you can call @builds.more(), that would play with offset and limit of the rest api to get more builds.