Make the token available about sharpbucket

[mnivet]

We have that but in current release it's only internal, not publicly exposed
see here: https://github.com/MitjaBezensek/SharpBucket/blob/master/SharpBucket/Authentication/OAuth2TokenProvider.cs

and we have a git clone usage in our unit tests.
See the usage of the token provider here:
https://github.com/MitjaBezensek/SharpBucket/blob/master/SharpBucketTests/GitHelpers/OAuth2GitCredentialsProvider.cs
And our git clone operation done with LibGit2Sharp in the constructor of that class:
https://github.com/MitjaBezensek/SharpBucket/blob/master/SharpBucketTests/GitHelpers/TestRepositoryBuilder.cs

I suppose we can easily expose to public the OAuth2TokenProvider if it match your needs
But for the OAuth2GitCredentialsProvider it won't be so simple. It depends on a git implementation (LibGit2Sharp) on which we don't want to take any dependency for the package we provide, and which may not be the one that you expect to use.
But if you use the same implementation, maybe we can though to provide a second package that provide that class. Or you can simply copy/past it in your own code, since creating a package for so little may not be relevant.

Take a look at those classes and tell me if just exposing the OAuth2TokenProvider to public would be good for you.

[mnivet]

OAuth2TokenProvider has been improved and will be exposed to public in the next release