Update maintainer list.

libs/maintainers.txt

@@ -97,6 +97,7 @@ polygon               Lucanus Simonson <lucanus.j.simonson -at- intel.com>, Andr
 pool                  Stephen Cleary <scleary -at- jerviswebb.com>
 predef                Rene Rivera <grafikrobot -at- gmail.com>
 preprocessor          Paul Mensonides <pmenso57 -at- comcast.net>
+process               Klemens D. Morgenstern <klemens.morgenstern -at- gmx.net>
 program_options       Vladimir Prus <vladimir.prus -at- gmail.com>
 property_map          Douglas Gregor <dgregor -at- cs.indiana.edu>
 property_tree         Sebastian Redl <sebastian.redl -at- getdesigned.at>