Update waterfall view

[tothandras]

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

[tardyp]

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.

[tardyp]

I think those are good improvements, and should be merged.
There is a need to improve the infinite scrolling, but this can be done later.

[djmitche]

I'll get it merged! You do have the power to merge, too ;)