Fix exit code and replicaset panic

[konoui]

address #9 , #10

I addressed issues at the same time since a fix of #10 is related to #9 .
If separating PR is required, please let me know.

Descriptions

• chage test directory to tests to match Makefile and README.md
• check a condition for each resource in the same workload
• add checking a condition of daemonset
• support ReplicaSet to avoid panic
  • there are several ways to avoid it e.g.) skip replicaset check, fallback to the pod handling, but I think adding it looks simple and useful.

[rothgar]

Thanks so much for the PR and open issues. I'll test this next week.