[FIX] Advances in snp_store adaption to new I/O module.

GFF support works now.
Merge branch 'feature/stream/develop' of github.com:esiragusa/seqan into feature/stream/adjust-snp_store
[FIX] Finishing adjustment of snp_store to new stream module.
[FIX,TEST] Fixing adjustment of snp_store tests to default quality value.

The default quality value changed from 60 to 40.  snp_store strongly
relies on the qualities for a lot of things.
[FIX] Fixing some issues with snp_store adaption to new stream module.
Merge pull request #42 from holtgrewe/feature/stream/adjust-snp_store

Adjusting snp_store new stream module.