When using stream_forecast_data I current get p50 fraction

[peterdudfield]

When Im getting lots of forecast data I used stream_forecast_data.
This returns p50_fraction data, but it would be useful to get p50_mw.

I can of course go and get the capacity at that time, but it would be useful if it was already returned, or already scaled

[devsjc]

You're right, this is missing - I'll add it in now

[devsjc]

Added with v0.13.2