Adding cyrtodactylus illumina reads to test data.
Adding fastq as supported format.
Updating seq conversion tests to deal with fastq.

Most formats cannot be converted to fastq format, because they
lack quality score data. Thus, the tests had to account for
the fact that you cannot convert to the fastq format.
Fixing doc typo.

Fixing typo in documentation for seqsift.dataio.get_seq_iter;
'sequenc' -> 'sequence'.