See #1404, closes #1929 [ci skip]

Add repo visibility and permission check for remote add command

`remote add` may now query the GitHub API to determine whether the
remote URL should be generated in writeable mode or not.

Add unix socket support

 Use 'scissors' to separate comments from PR messages 

This allows PR templates to include markdown headers with '#'

Add the command `hub issue show <NUMBER>`

This commit adds the subcommand hub issue view, which displays an issue as well as
lists its comments underneath.

Add ability to list requested reviewers with `%rs`

Fixes #1913

Fixes #1913

Adding unit tests for util methods

The default direction when sorting by `created` date (the default) is
descending. However, the default on the API backend changes to ascending
when the sort key is something different than `created`:
https://developer.github.com/v3/pulls/#list-pull-requests

This ensures that the default `direction: "desc"` is always passed to
API queries, regardless of the sort key, unless `--sort-ascending` was used.

Ref. https://github.com/github/hub/issues/1815#issuecomment-433222344

Update --labels documentation to show it will be created if not exists

fix `compare` command if not on any branch

There is no need to detect the current branch if a range is provided
as an argument.

Fixes #1584.

Fixed CI status check exit code.

For `hub release show`, `MainProject()` was used to fetch the canonical
repo of the current project. However, the `create`, `edit`, and `delete`
operations used `CurrentProject()` most likely by mistake. This caused
the `hub release edit` operation, for example, to be potentially
performed against a fork rather than the canonical repo, depending on
the currenly checked out branch.

Fixes #1881

[ci skip]

Fixes #1866 [ci skip]

Fixes #1863 [ci skip]

commands/clone: fix typo in docs

If you're trying to create `owner/foo` repo and there is an existing
redirect from `owner/foo` to a differently name repo, don't consider
that one as an existing repo and proceed with creating `owner/foo`.

Prevent setting a public upstream when creating a private repo.