Add myself as asio maintainer.

[SVN r40875]

libs/maintainers.txt

@@ -2,6 +2,7 @@ algorithm/minmax      Herve Bronnimann <hbr -at- poly.edu>
 algorithm/string      Pavol Droba <droba -at- topmail.sk>
 any                   Alexander Nasonov <alexander.nasonov -at- gmail.com>
 array
+asio                  Chris Kohlhoff <chris -at- kohlhoff.com>
 assign                Thorsten Ottosen <nesotto -at- cs.auc.dk>
 bimap                 Matias Capeletto <matias.capeletto -at- gmail.com>
 bind                  Peter Dimov <pdimov -at- mmltd.net>