Consolidate committer info

[haacked]

Replace SignatureResponse and CommitEntity with Committer

A recent PR added CommitEntity but we already had SignatureResponse expressly for this purpose.

So this commit renames SignatureResponse to Committer and removes CommitEntity and replaces it with Committer.

I also had to retarget the NetCore45 app so it builds in VS 2015.

[haacked]

/cc @WillsB wanted to make sure you saw this change.

[heytherewill]

My bad, didn't know about this one. But why was GitHubCommit changed back to use Author instead of Committer? (that was the initial issue)

[haacked]

My bad, didn't know about this one. But why was GitHubCommit changed back to use Author instead of Committer? (that was the initial issue)

Because according to the docs here, the author and committer for a GitHubCommit correspond to a GitHub account (aka Author).

The commit property of GitHubCommit also has author and committer but those correspond to Committer.

I think the confusion stems from the fact that the API returns GitHub objects as well as Git objects and Octokit.net has confused the two in some places.

A Committer is the minimal signature that a Git commit contains {'name', 'email', 'date'}. GitHub will try to associate a committer (and author) of a Git commit to a GitHub account. It can't always do that and now that I think about it, I'm not sure what it responds when it can't.

[haacked]

I commented on the original issue