Supervisor children are not guranteed to be atoms. Fixes issue #33

src/error_logger_lager_h.erl

@@ -179,7 +179,7 @@ format_offender(Off) ->
             %% regular supervisor
             MFA = format_mfa(MFArgs),
             Name = proplists:get_value(name, Off),
-            io_lib:format("~s started with ~s at ~w",
+            io_lib:format("~p started with ~s at ~w",
                 [Name, MFA, proplists:get_value(pid, Off)])
     end.