added midpoint rooting before OG rooting

-midpoint rooting was necessary because the tree was rooted by one of the taxa in the
outgroup clade, causing the entire tree to be selected as the outgroup clade
added ability to search for group representatives by accession number
updated with sequences that were in DB but missing from sequence dataset
renamed stats file to keep consistent with all other files
updated with sequences that were in DB but missing from sequence dataset
modified the branch thicknesses for the pdf output
renamed phyml stats file to be consistent with all other file names