migrate to upstream libcompose in one and a half go

vendor/github.com/gorilla/mux/doc.go

@@ -89,7 +89,7 @@ There are several other matchers that can be added. To match path prefixes:
 
 	r.MatcherFunc(func(r *http.Request, rm *RouteMatch) bool {
 		return r.ProtoMajor == 0
-	})
+    })
 
 ...and finally, it is possible to combine several matchers in a single route:
 
@@ -164,21 +164,14 @@ This also works for host variables:
 
 	// url.String() will be "http://news.domain.com/articles/technology/42"
 	url, err := r.Get("article").URL("subdomain", "news",
-	                                 "category", "technology",
-	                                 "id", "42")
+									 "category", "technology",
+									 "id", "42")
 
 All variables defined in the route are required, and their values must
 conform to the corresponding patterns. These requirements guarantee that a
 generated URL will always match a registered route -- the only exception is
 for explicitly defined "build-only" routes which never match.
 
-Regex support also exists for matching Headers within a route. For example, we could do:
-
-	r.HeadersRegexp("Content-Type", "application/(text|json)")
-
-...and the route will match both requests with a Content-Type of `application/json` as well as
-`application/text`
-
 There's also a way to build only the URL host or path for a route:
 use the methods URLHost() or URLPath() instead. For the previous route,
 we would do:
@@ -200,7 +193,7 @@ as well:
 
 	// "http://news.domain.com/articles/technology/42"
 	url, err := r.Get("article").URL("subdomain", "news",
-	                                 "category", "technology",
-	                                 "id", "42")
+									 "category", "technology",
+									 "id", "42")
 */
 package mux