Preserve resources when guessing actions

[flosell]

#22 introduced a feature to guess actions that are similar to an existing policy. It currently always guesses * resources.
Extend this feature so that resources are preserved as appropriate:

Input

{
  "Action": ["s3:PutObject"],
  "Effect": "Allow",
  "Resource": ["arn:aws:s3:::some-bucket"]
}

Expected guess:

{
  "Action": [ "s3:DeleteObject","s3:GetObject","s3:ListObjects"],
  "Effect": "Allow",
  "Resource": ["arn:aws:s3:::some-bucket"]
}

Pitfall: Some actions only support "*"!