supervisor simple_one_for_one实例,别人原创
http://www.cnblogs.com/little-ant/archive/2013/07/17/3196201.html
运行结果：
2> c(simple_sup).
{ok,simple_sup}
5> c(normal_process).
{ok,normal_process}
6> c(gen_server_process).
{ok,gen_server_process}
8> simple_sup:start_link().
{ok,<0.66.0>}
9> supervisor:start_child(simple_sup, []).
{ok,<0.68.0>}
10> gen_server_process:echo("aaaa").
"aaaa"
3> simple_sup:start_link().
{ok,<0.37.0>}
4> {ok, Pid} = supervisor:start_child(simple_sup, []).
{ok,<0.39.0>}
5> Pid ! "normal".
"normal"