Initial fix for BAM experiment data

This fixes the initial bug reported under #6 but raises another question over why it fails. 

It _appears_ to be something to do with Postgres but I'm unsure whether there's anything specific about the bam file processing in the controller. It does _far less_ than for the GFF, that's for sure.

Can you explain the BAM file processing to me so I can review further, or provide any other insight? Was this definitely working under the original experimental branch?