I/O for sequencing file formats

Versions of BioSequences prior to v2.0 provided a FASTA, FASTQ, and 2Bit submodule for working with formatted sequence files.

After version v2.0, in order to neatly separate concerns, these submodules were removed.

Instead there will now be dedicated BioJulia packages for each format. Each of these will be compatible with BioSequences.

A list of all of the different formats and packages is provided below to help you find them quickly.