WIP: split libraries from SFFs

Design is to support:

* SFFs
* fasta
* fasta and qual

Specific parameters such as barcode type will be sourced from db. Finalizing this will require touching a few other areas of the codebase and a db patch, which I'll get to as they become necessary.

~~**This is not tested, and not mergable yet**~~
There were conflicts that arose as @josenavas was working on patches at the same time I was, which made it really difficult to stay in sync with master. 

In practice, it is correct to have newlines anyway at the end of a file, so I recommend keeping this.