Correct method to detect if node is online or offline

[Gregorio Di Stefano]

Hi, 

Another question regarding the correct method to determine if a node is alive or not:

We rely on the member API to determine that status of nodes, but, find it weird that that status codes for member status are enum type without any constants set in the Go library. 

The only way to find out what these actual int values mean is by looking at the product source code: https://github.com/hashicorp/consul/blob/v0.6.4/vendor/github.com/hashicorp/serf/serf/serf.go#L148 to determine what they actually mean.

This give me the impression we are doing something incorrectly.

Thanks

[schri...@hashicorp.com]

Howdy again Greg,

Those integers being returned aren't super clear. I went ahead and opened up this PR to be able to provide more clarification. 

We cannot replace the status integers being returned because any change like that would be considered a breaking change and would not be backwards compatible. I hope this helps, though.

- Sarah