Revert the router's path string decoding strategy (fixes #3064)

api/router.js

@@ -52,7 +52,12 @@ module.exports = function($window, mountRedraw) {
 				if (prefix[0] !== "/") prefix = "/" + prefix
 			}
 		}
-		var path = decodeURIComponentSafe(prefix).slice(route.prefix.length)
+		// This seemingly useless `.concat()` speeds up the tests quite a bit,
+		// since the representation is consistently a relatively poorly
+		// optimized cons string.
+		var path = prefix.concat()
+			.replace(/(?:%[a-f89][a-f0-9])+/gim, decodeURIComponentSafe)
+			.slice(route.prefix.length)
 		var data = parsePathname(path)
 
 		Object.assign(data.params, $window.history.state)

api/tests/test-routerGetSet.js

@@ -220,7 +220,7 @@ o.spec("route.get/route.set", function() {
 					route.set("/other/:a/:b", {a: "x", b: "y/z", c: "d", e: "f"})
 					setTimeout(function() {
 						// Yep, before even the throttle mechanism takes hold.
-						o(route.get()).equals("/other/x/y/z?c=d&e=f")
+						o(route.get()).equals("/other/x/y%2Fz?c=d&e=f")
 						throttleMock.fire()
 						done()
 					})

pathname/compileTemplate.js

@@ -1,6 +1,7 @@
 "use strict"
 
 var parsePathname = require("./parse")
+var decodeURIComponentSafe = require("../util/decodeURIComponentSafe")
 
 // Compiles a template into a function that takes a resolved path (without query
 // strings) and returns an object containing the template parameters with their
@@ -36,7 +37,7 @@ module.exports = function(template) {
 		var values = regexp.exec(data.path)
 		if (values == null) return false
 		for (var i = 0; i < keys.length; i++) {
-			data.params[keys[i].k] = keys[i].r ? values[i + 1] : decodeURIComponent(values[i + 1])
+			data.params[keys[i].k] = keys[i].r ? values[i + 1] : decodeURIComponentSafe(values[i + 1])
 		}
 		return true
 	}