remove autoconf and automake, add make instead

See https://github.com/taobao/nginx-book/issues/134
增加ngx_str_t变量定义之后再赋值的一种方法

See https://github.com/taobao/nginx-book/issues/139
移除ngx_prealloc()

See https://github.com/taobao/nginx-book/issues/140
Merge branch 'master' of https://github.com/ideal/nginx-book