Add annotations to output

[maehler]

It should be possible to output annotations together with the sequences (given that annotations are given in the input). Consequently, the user should be able to choose between fasta and genbank (and possibly fasta + gff) as output.

[maehler]

I think that the standard output format for in silico PCR should be fasta, while for operon extraction, the format should match the input format.