Fix typos in README

Signed-off-by: Chengwei Yang <yangchengwei@qiyi.com>
Fix default value of mesos_task_mem and mesos_task_disk in README

Signed-off-by: Chengwei Yang <yangchengwei@qiyi.com>
Fix reporting bugs link in FAQ

Signed-off-by: Chengwei Yang <yangchengwei@qiyi.com>