fix references on main page

We should probably have consistent references on the main site. Something like this:

andi for tree building:

B Haubold, F Klötzl, and P Pfaffelhuber. andi: fast and accurate estimation of evolutionary distances between closely related genomes. Bioinformatics, 2015 vol. 31 (8) pp. 1169-1175.

MCL for REPIN population clustering:

A J Enright, S Van Dongen, and C A Ouzounis. An efficient algorithm for large-scale detection of protein families. Nucleic Acids Research, 2002 vol. 30 (7) pp. 1575-1584.

BLAST+ for identifying RAYT relatives in the different genomes:

C Camacho, G Coulouris, V Avagyan, N Ma, J Papadopoulos, K Bealer, and T L Madden. BLAST+: architecture and applications. BMC Bioinformatics, 2009 vol. 10 (1) pp. 421-9.