vendorize: update all vendorized packages. (#2206)

Bring in new changes from upstream for all the packages.

Important ones include
   - gorilla/mux
   - logrus
   - jwt

vendor/github.com/rs/xhandler/README.md

@@ -0,0 +1,134 @@
+# XHandler
+
+[![godoc](http://img.shields.io/badge/godoc-reference-blue.svg?style=flat)](https://godoc.org/github.com/rs/xhandler) [![license](http://img.shields.io/badge/license-MIT-red.svg?style=flat)](https://raw.githubusercontent.com/rs/xhandler/master/LICENSE) [![Build Status](https://travis-ci.org/rs/xhandler.svg?branch=master)](https://travis-ci.org/rs/xhandler) [![Coverage](http://gocover.io/_badge/github.com/rs/xhandler)](http://gocover.io/github.com/rs/xhandler)
+
+XHandler is a bridge between [net/context](https://godoc.org/golang.org/x/net/context) and `http.Handler`.
+
+It lets you enforce `net/context` in your handlers without sacrificing compatibility with existing `http.Handlers` nor imposing a specific router.
+
+Thanks to `net/context` deadline management, `xhandler` is able to enforce a per request deadline and will cancel the context when the client closes the connection unexpectedly.
+
+You may create your own `net/context` aware handler pretty much the same way as you would do with http.Handler.
+
+Read more about xhandler on [Dailymotion engineering blog](http://engineering.dailymotion.com/our-way-to-go/).
+
+## Installing
+
+    go get -u github.com/rs/xhandler
+
+## Usage
+
+```go
+package main
+
+import (
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/rs/cors"
+	"github.com/rs/xhandler"
+	"golang.org/x/net/context"
+)
+
+type myMiddleware struct {
+	next xhandler.HandlerC
+}
+
+func (h myMiddleware) ServeHTTPC(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+	ctx = context.WithValue(ctx, "test", "World")
+	h.next.ServeHTTPC(ctx, w, r)
+}
+
+func main() {
+	c := xhandler.Chain{}
+
+	// Add close notifier handler so context is cancelled when the client closes
+	// the connection
+	c.UseC(xhandler.CloseHandler)
+
+	// Add timeout handler
+	c.UseC(xhandler.TimeoutHandler(2 * time.Second))
+
+	// Middleware putting something in the context
+	c.UseC(func(next xhandler.HandlerC) xhandler.HandlerC {
+		return myMiddleware{next: next}
+	})
+
+	// Mix it with a non-context-aware middleware handler
+	c.Use(cors.Default().Handler)
+
+	// Final handler (using handlerFuncC), reading from the context
+	xh := xhandler.HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, r *http.Request) {
+		value := ctx.Value("test").(string)
+		w.Write([]byte("Hello " + value))
+	})
+
+	// Bridge context aware handlers with http.Handler using xhandler.Handle()
+	http.Handle("/test", c.Handler(xh))
+
+	if err := http.ListenAndServe(":8080", nil); err != nil {
+		log.Fatal(err)
+	}
+}
+```
+
+### Using xmux
+
+Xhandler comes with an optional context aware [muxer](https://github.com/rs/xmux) forked from [httprouter](https://github.com/julienschmidt/httprouter):
+
+```go
+package main
+
+import (
+	"fmt"
+	"log"
+	"net/http"
+	"time"
+
+	"github.com/rs/xhandler"
+	"github.com/rs/xmux"
+	"golang.org/x/net/context"
+)
+
+func main() {
+	c := xhandler.Chain{}
+
+	// Append a context-aware middleware handler
+	c.UseC(xhandler.CloseHandler)
+
+	// Another context-aware middleware handler
+	c.UseC(xhandler.TimeoutHandler(2 * time.Second))
+
+	mux := xmux.New()
+
+	// Use c.Handler to terminate the chain with your final handler
+	mux.GET("/welcome/:name", xhandler.HandlerFuncC(func(ctx context.Context, w http.ResponseWriter, req *http.Request) {
+		fmt.Fprintf(w, "Welcome %s!", xmux.Params(ctx).Get("name"))
+	}))
+
+	if err := http.ListenAndServe(":8080", c.Handler(mux)); err != nil {
+		log.Fatal(err)
+	}
+}
+```
+
+See [xmux](https://github.com/rs/xmux) for more examples.
+
+## Context Aware Middleware
+
+Here is a list of `net/context` aware middleware handlers implementing `xhandler.HandlerC` interface.
+
+Feel free to put up a PR linking your middleware if you have built one:
+
+| Middleware | Author | Description |
+| ---------- | ------ | ----------- |
+| [xmux](https://github.com/rs/xmux) | [Olivier Poitrey](https://github.com/rs) | HTTP request muxer |
+| [xlog](https://github.com/rs/xlog) | [Olivier Poitrey](https://github.com/rs) | HTTP handler logger |
+| [xstats](https://github.com/rs/xstats) | [Olivier Poitrey](https://github.com/rs) | A generic client for service instrumentation |
+| [xaccess](https://github.com/rs/xaccess) | [Olivier Poitrey](https://github.com/rs) | HTTP handler access logger with [xlog](https://github.com/rs/xlog) and [xstats](https://github.com/rs/xstats) |
+| [cors](https://github.com/rs/cors) | [Olivier Poitrey](https://github.com/rs) | [Cross Origin Resource Sharing](http://www.w3.org/TR/cors/) (CORS) support |
+
+## Licenses
+
+All source code is licensed under the [MIT License](https://raw.github.com/rs/xhandler/master/LICENSE).