Migrate to dep (#3972)

* Update makefile to use dep

* Migrate to dep

* Fix some deps

* Try to find a better version for golang.org/x/net

* Try to find a better version for golang.org/x/oauth2

vendor/gopkg.in/gomail.v2/CHANGELOG.md

@@ -1,20 +0,0 @@
-# Change Log
-All notable changes to this project will be documented in this file.
-This project adheres to [Semantic Versioning](http://semver.org/).
-
-## [2.0.0] - 2015-09-02
-
-- Mailer has been removed. It has been replaced by Dialer and Sender.
-- `File` type and the `CreateFile` and `OpenFile` functions have been removed.
-- `Message.Attach` and `Message.Embed` have a new signature.
-- `Message.GetBodyWriter` has been removed. Use `Message.AddAlternativeWriter`
-instead.
-- `Message.Export` has been removed. `Message.WriteTo` can be used instead.
-- `Message.DelHeader` has been removed.
-- The `Bcc` header field is no longer sent. It is far more simpler and
-efficient: the same message is sent to all recipients instead of sending a
-different email to each Bcc address.
-- LoginAuth has been removed. `NewPlainDialer` now implements the LOGIN
-authentication mechanism when needed.
-- Go 1.2 is now required instead of Go 1.3. No external dependency are used when
-using Go 1.5.

vendor/gopkg.in/gomail.v2/CONTRIBUTING.md

@@ -1,20 +0,0 @@
-Thank you for contributing to Gomail! Here are a few guidelines:
-
-## Bugs
-
-If you think you found a bug, create an issue and supply the minimum amount
-of code triggering the bug so it can be reproduced.
-
-
-## Fixing a bug
-
-If you want to fix a bug, you can send a pull request. It should contains a
-new test or update an existing one to cover that bug.
-
-
-## New feature proposal
-
-If you think Gomail lacks a feature, you can open an issue or send a pull
-request. I want to keep Gomail code and API as simple as possible so please
-describe your needs so we can discuss whether this feature should be added to
-Gomail or not.

vendor/gopkg.in/gomail.v2/README.md

@@ -1,92 +0,0 @@
-# Gomail
-[![Build Status](https://travis-ci.org/go-gomail/gomail.svg?branch=v2)](https://travis-ci.org/go-gomail/gomail) [![Code Coverage](http://gocover.io/_badge/gopkg.in/gomail.v2)](http://gocover.io/gopkg.in/gomail.v2) [![Documentation](https://godoc.org/gopkg.in/gomail.v2?status.svg)](https://godoc.org/gopkg.in/gomail.v2)
-
-## Introduction
-
-Gomail is a simple and efficient package to send emails. It is well tested and
-documented.
-
-Gomail can only send emails using an SMTP server. But the API is flexible and it
-is easy to implement other methods for sending emails using a local Postfix, an
-API, etc.
-
-It is versioned using [gopkg.in](https://gopkg.in) so I promise
-there will never be backward incompatible changes within each version.
-
-It requires Go 1.2 or newer. With Go 1.5, no external dependencies are used.
-
-
-## Features
-
-Gomail supports:
-- Attachments
-- Embedded images
-- HTML and text templates
-- Automatic encoding of special characters
-- SSL and TLS
-- Sending multiple emails with the same SMTP connection
-
-
-## Documentation
-
-https://godoc.org/gopkg.in/gomail.v2
-
-
-## Download
-
-    go get gopkg.in/gomail.v2
-
-
-## Examples
-
-See the [examples in the documentation](https://godoc.org/gopkg.in/gomail.v2#example-package).
-
-
-## FAQ
-
-### x509: certificate signed by unknown authority
-
-If you get this error it means the certificate used by the SMTP server is not
-considered valid by the client running Gomail. As a quick workaround you can
-bypass the verification of the server's certificate chain and host name by using
-`SetTLSConfig`:
-
-    package main
-
-    import (
-    	"crypto/tls"
-
-    	"gopkg.in/gomail.v2"
-    )
-
-    func main() {
-    	d := gomail.NewDialer("smtp.example.com", 587, "user", "123456")
-    	d.TLSConfig = &tls.Config{InsecureSkipVerify: true}
-
-        // Send emails using d.
-    }
-
-Note, however, that this is insecure and should not be used in production.
-
-
-## Contribute
-
-Contributions are more than welcome! See [CONTRIBUTING.md](CONTRIBUTING.md) for
-more info.
-
-
-## Change log
-
-See [CHANGELOG.md](CHANGELOG.md).
-
-
-## License
-
-[MIT](LICENSE)
-
-
-## Contact
-
-You can ask questions on the [Gomail
-thread](https://groups.google.com/d/topic/golang-nuts/jMxZHzvvEVg/discussion)
-in the Go mailing-list.