API methods

[maciej-gurban]

Hi! Very interesting project. Thanks a lot for sharing!

I was wondering whether you'd consider revising naming conventions to be a bit less verbose and closer to git's syntax. What I mean is:

const git = new GitKit({
  repo: REPOSITORY_URL,
  user: REPOSITORY_USER
});

git.commit('initial commit, '*');
git.commit('initial commit, [
  'app.js',
  'scripts.js'
]);

git.branch.current()
git.branch.checkout('develop/feature/profile-update')

Not all of them would be as simple of course, since checkout() might also need to be accompanied by checkoutNew etc. but I hope you know what I mean.