Script to save qc-data from RNA-seq pipe to file

Thanks for the explanation @mayabrandi! As we're doing paired-end alignment, should we be looking at `Reads mapped in proper pairs` (corresponding to @vezzi's comment about molecules) instead of `Read-1` and `Read-2`?

It doesn't make a huge difference, but it will report more alignments: `20055034` vs.
```
(15956601 + 15854150) / 2 = 15905376
```

As you say though, not worth loosing sleep over as we'll probably be using a different metric some time in next year..