It includes the latest changes from `go-octokit`

gh: Fix merge PR title to be followed with proper new line

Now, merge pull-request makes a commit like:

    Merge pull request #8 from yasuoza/blahblah\n\nOriginal Pull Request Title

This commit fixes it to:

    Merge pull request #8 from yasuoza/blahblah

    Original Pull Request Title

Remove Ruby-specific parts of docs in prep for move to Go

As the Go version of hub matures, we plan to add features that are not
necessarily tied to git operations, such as viewing and managing issues.

Previously this wan't in the scope of the project. Now the scope widens.

- Ruby is not required at runtime anymore
- Most installation instructions are now obsolete. Will need to write
  new instructions when we distribute precompiled binaries.
- Remove tedious parts about slowness. It's not slow anymore!

Use "text/template" instead of "html/" to not have HTML-escaping

This lets github.project implement its own comparison logic. For
instance, two projects can be the same even though their `Protocol`
values don't match.

Otherwise, characters like quotes, less/greater than signs, and
ampersand would get HTML-escaped in the text editor for the pull request
message.

Port latest batch of cukes from master to gh

This allows someone to have something like this in their SSH config:

    Host gh
      HostName github.com

And then use git remote URLs such as:

    gh:myname/myrepo.git

Since git itself allows people to do this, we need to support it in hub.

Port `cherry-pick`, `pull-request` tests to cukes

Port a bunch more tests to cukes

[gh] Merge in master (v1.12.2) and fix all tests

Fix `git --noop clone` with private repos

Fixes #593

expect(x).to_not returns false when the test passes, so using history.all? only
checks the first element of the list. Since expect raises anyway, we
don't need to bother anyway.