Add option to formats.gff.load() to generate full header (partly based
upon Athaliana FASTA headers) which contain seqid, start/end coords and
datestamp (for generating annotation release). Add option to
formats.gff.format() to allow appending a `Name` attribute from a
two-column lookup table. Rename `--switch` option to `--seqid`. Add
option to annotation.reformat.annotate() which lets user specify if
identifiers in the the BED file used for annotation follow the ATG
naming convention or not (eg. Medtr1g0010000, At2g00348, etc.)