John Langford <jl@hunch.net>
... and many others.  The git log includes at least:

 Alekh Agarwal 
 Ales Tamchyna 
 ariel faigon 
 Ben Gimpert 
 Bharath Krishnan 
 Brian Muller 
 Chris Quirk 
 Daniel Erenrich 
 Daniel Hsu 
 Gordon Rios 
 Hal Daume III 
 Ivan Dyedov 
 Jacob Hofman 
 Jake Hofman 
 Jan Szumiec 
 John Langford 
 Lihong Li 
 Luis Pedro Coelho 
 Marcel Laverdet 
 Matthew Hoffman 
 Nikos Karampatziakis 
 Paul Mineiro 
 Sergei Matusevich 
 Shravan M Narayanamurthy 
 Stephane Ross 
 Stephen Merity 
 Vaclav Petricek 
 Yaroslav Halchenko