Closes #517 [ci skip]

Hub merge should use repo name from API

The repository name of the pull request head doesn't necessarily match
the name of the project's repository. This can happen when a user forks
a project but already has a repository of the same name. Use the name
returned in the api response for the fetch url to avoid this edge case.

It shells out to other Ruby scripts, but we don't want them to inherit
the same bundle as the hub project. So we clear RUBYOPT which in a
Bundler environment contains `-rbundler/setup`.

`less -X` prevents clearing of screen, but we want these commands to
clear themselves up on exit, i.e. to not litter people's output buffers:

    git help hub
    hub <command> --help

Fixes #368

If someone misspells `--help`, for instance:

    git pull-request -help

This aborts the command instead of continuing by interpreting `-help` as
it was the deprecated title argument. Any value that starts with a dash
will abort.

Fixes #460

Enable API debug output by setting HUB_VERBOSE

Hashes are unordered in Ruby 1.8, so we can't check for this in debug
output: `{"name": "dotfiles", "private": false}`. The keys might appear
in different order.

A proper fix would be to normalize keys order before output assertion in
tests, but I can't be bothered to make that. Here I'm simply avoiding to
make any assertions for that line.

https://travis-ci.org/github/hub/jobs/19817554

This will print information about every HTTP request and response to
stderr. Authentication info is redacted.

Example:

    $ HUB_VERBOSE=1 hub ci-status
    > GET https://api.github.com/...
    > ...

For people who are using hub for a longer time now, hub has stored an OAuth
token in Authorizations API with a `note_url` value that is now outdated
(e.g. "http://defunkt.io/hub/"). The newer `oauth_app_url` doesn't match
that, so the token is not reused. Hub tries to create a new OAuth token
with a `note` that says "hub" which fails with a 422 because it already
exists.

This fixes reusing old OAuth tokens even if the `note_url` doesn't match
anymore. Any key with `note` that says "hub" will get reused.

Fixes #496

Technically, they're going to be the same values for OAuth tokens
created via the API, but since we write to `note_url` field it makes
sense to use the same field to read the value back, for consistency.

This is so that a user-friendly message is shown instead of a useless
stack trace.

Previously, these errors would not be shown to the user, which would
lead to some very uninformative HTTP error messages.

This is so the next shell prompt isn't displayed on the same line where
the interrupted hub prompt is.

This is irrelevant in zsh, which ensures that the prompt always starts
on its own line.

Add option to open newly created pull request in the browser.

Closes #344

Allow Enterprise configured for regular HTTP

Allows using these commands for Enterprise configurations over regular HTTP.

Example `~/.config/hub`:

  my.example.org:
  - user: myuser
    oauth_token: mytoken
    protocol: http

Currently there is no way to set `protocol` other than manually editing the
configuration file.

Since we use a test server representing the GitHub API, all requests get
transformed to HTTP in tests. Make a check that the original requests
really was intended to go over HTTPS.

Fixes CI in forked environment and enables usage of `cached-bundle`
script to just restore caches from S3 but never attempt to write them.

We can't let email configuration be the default since it would spam most
people in the GitHub org. However, we set it to a couple of addresses
explicitly, we get emailed with failures from other people's forks who
have set up CI for themselves.

If the user is currently on the "feature" branch that is pushed to their
fork, when they do `hub browse -- issues` it should open issues of the
main (canonical) repository, not that of the fork.

When a user would do `hub browse` on the master branch and they had a
fork, the hub would open the browser with their fork instead of the
upstream project. This is surprising and unwanted, so I've added an
exception for this case.

Fixes #474

Fixes #470

Fix `hub fork` command in cases when GitHub fork is not yet ready for fetching

Forking through GitHub's API is asynchronous so there is really no way
of knowning when you can access git objects without polling.
Alternatively, we can establish the state of the fork with its remote
tracking branches and tags by fetching from the "origin" remote and then
changing the remote url to the fork.

Avoids the issue where leading empty lines would result in an empty
pull request title.

Fixes #439, closes #465

This only affects CI builds in cases when the bundle is not cached.

Fixes test failures with Boxen git 1.8.2-boxen1

They emit Ruby warnings on Ruby 2.1.0

Fixes #466