The Gaia-ESO Survey: processing FLAMES-UVES spectra by Sacco, G, Morbidelli, L, Franciosini, E, Majorca, E, Randich, S, Modigliani, A, Gilmore, G, Asplund, M, Binney, J, Bordfacio, P, Drew, J, Feltzing, S, Ferguson, A, Jeffries, R, Micela, G, Negueruela, I, Prusti, T, Rix, H, Vallenari, A, Alfaro, E, Prieto, C, Babusiaux, C, Bensby, T, Blomme, R, Bragaglia, A