These people have contributed useful patches, ideas and suggestions:

Andre Costa
Aredridel
Balázs Szabó
Bardur Arantsson
Benj. Mako Hill
Christoph Dworzak
Christopher Rosado
Chung-chieh Shan
Corrin Lakeland
Dan Egnor
Daniel Jacobowitz
Dirk Huebner
Emil Sit
Felipe Gustavo de Almeida
Ico Doornekamp
James Leifer
Jerry Jorgenson
Joerg Desch
John Arthur Kane
John Keener
Josh Purinton
Kevin Rosenberg
Martin Danielsson
Mikael Ylikoski
Paramjit Oberoi
Peter Chines
Robert Hofer
Roberto Boati
Samuel Tardieu
Sanjoy Mahajan
Satyaki Das
Vincent Lefevre
Vladimir V. Kisil
Will Yardley
Wolfgang Weisselberg

I apologise to any contributors who have been omitted from this list!