Use secure_tmp_dir for Excel::Writer::XLSX.
Genome Comparator: Align after each locus rather than at the end.
This removes the need to store all the extracted sequences so should
save memory.
Fix memory leak in offline jobs when output large amounts of data.
Genome Comparator: Fix Excel output of unique strains.
Table needs to be written in sequential row order since switching on
memory optimizations in Excel::Writer::XLSX.