Add Kevin, Adam, and Vicent to the THANKS file.

THANKS

@@ -3,6 +3,7 @@ Gumbo HTML parser THANKS file
 Gumbo was originally written by Jonathan Tang, but many people helped out through suggestions, question-answering, code reviews, bugfixes, and organizational support.  Here is a list of these people.  Help me keep it complete and exempt of errors.
 
 Adam Barth
+Adam Roben
 Ben Noordhuis
 Bowen Han
 Constantinos Michael
@@ -11,6 +12,7 @@ Geoffrey Sneddon
 Ian Hickson
 Jack Deng
 Jonathan Shneier
+Kevin Hendricks
 Mason Tang
 Maxim Zakharov
 Neal Norwitz
@@ -20,3 +22,4 @@ Stefan Haustein
 Steffen Meschkat
 Steven Kabbes
 Thiago Farina
+Vicent Marti