Allow commits on any unparented branch

[jamill]

LibGit2Sharp will currently only allow a commit on an "orphaned" or unparented branch if the libgit2 repository is "empty" - in particular, an initial commit is only allowed on the "master" branch.

This PR changes the condition that is checked for the initial commit to see if the current branch is orphaned.

[nulltoken]

@jamill How about also deprecating the repo.Info.IsEmpty?

Do anyone use this?

/cc @spraints @haacked @carlosmn

[jamill]

@nulltoken ok - I marked the property as obsolete and removed most of the places we use this property internally. There is one place that I do not quite understand the code yet, so I left it as is for now (in CommitLog)...

[spraints]

@nulltoken I don't see anything in git-tfs that uses repo.Info.IsEmpty.

[nulltoken]

@jamill I do like this very much!

There is one place that I do not quite understand the code yet, so I left it as is for now (in CommitLog)...

This is indeed a very crappy and fragile piece of code. This comes from #30.

If you comment out the code that returns Enumerable.Empty<>, some tests should fail.

If you can think of a safer implementation, that would be awesome!

[nulltoken]

Very thoughtful job! Merged. 🎱 :

If you can think of a safer implementation, that would be awesome!

The [Obsolete] warning will be in our face each time we compile. We'll tackle this later!