Inconsistent Timeline behavior

[orweinberger]

When playing around with the timeframe and interval of a Timeline, I've noticed some inconsistencies.

How to reproduce:

1. Use the example code to push some user visits data into Joola (elasticsearch provider).
2. Include jQuery and joola.js on a blank page
3. Add the following code and change the timeframe and interval vars.

Examples that show the inconsistencies:

• timeframe = last_hour, interval = second -> Produces a chart with no values.
• timeframe = last_day, interval = minute -> Produces n chart with no values.
• timeframe = last_30_days, interval = day -> Shows a negative yAxis (values are correct)

[orweinberger]

I've switched to feature/#175 and still get inconsistent behaviors (after running grunt build). The top two points above still produce empty charts (looks a bit different than before), the third point still occurs exactly as it did before.