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/github.com/Unknwon/com/README.md

@@ -1,20 +0,0 @@
-Common Functions
-================
-
-[![Build Status](https://travis-ci.org/Unknwon/com.svg)](https://travis-ci.org/Unknwon/com) [![Go Walker](http://gowalker.org/api/v1/badge)](http://gowalker.org/github.com/Unknwon/com)
-
-This is an open source project for commonly used functions for the Go programming language.
-
-This package need >= **go 1.2**
-
-Code Convention: based on [Go Code Convention](https://github.com/Unknwon/go-code-convention).
-
-## Contribute
-
-Your contribute is welcome, but you have to check following steps after you added some functions and commit them:
-
-1. Make sure you wrote user-friendly comments for **all functions** .
-2. Make sure you wrote test cases with any possible condition for **all functions** in file `*_test.go`.
-3. Make sure you wrote benchmarks for **all functions** in file `*_test.go`.
-4. Make sure you wrote useful examples for **all functions** in file `example_test.go`.
-5. Make sure you ran `go test` and got **PASS** .