Do we need all datasets in SRC output of waterfall module?

@npaszty
please see sample app SRC output

NEST/teal.osprey/blob/master/R/tm_g_waterfall.R#L140). I think it can be improved to limit only those of interest in encoding panel.

The issue existed in the December release thus moving it to the main backlog

Provenance:
```
Creator: pawelru
```