Officially drop IE9-10 support, pull out our hacks (#2296)

- I also fixed a bunch of related comments
- I had to polyfill `requestAnimationFrame` for Node
- Drive-by: run `eslint . --fix`
- Drive-by: update transpiling info in CONTRIBUTING.md
- Drive-by: we aren't the only ones going semicolon-free

api/redraw.js

@@ -3,18 +3,13 @@
 var coreRenderer = require("../render/render")
 
 function throttle(callback) {
-	//60fps translates to 16.6ms, round it down since setTimeout requires int
-	var delay = 16
-	var last = 0, pending = null
-	var timeout = typeof requestAnimationFrame === "function" ? requestAnimationFrame : setTimeout
+	var pending = null
 	return function() {
-		var elapsed = Date.now() - last
 		if (pending === null) {
-			pending = timeout(function() {
+			pending = requestAnimationFrame(function() {
 				pending = null
 				callback()
-				last = Date.now()
-			}, delay - elapsed)
+			})
 		}
 	}
 }

api/tests/test-redraw.js

@@ -5,6 +5,19 @@ var domMock = require("../../test-utils/domMock")
 var throttleMocker = require("../../test-utils/throttleMock")
 var apiRedraw = require("../../api/redraw")
 
+// Because Node doesn't have this.
+if (typeof requestAnimationFrame !== "function") {
+	global.requestAnimationFrame = (function (delay, last) {
+		return function(callback) {
+			var elapsed = Date.now() - last
+			return setTimeout(function() {
+				callback()
+				last = Date.now()
+			}, delay - elapsed)
+		}
+	})(16, 0)
+}
+
 o.spec("redrawService", function() {
 	var root, redrawService, $document
 	o.beforeEach(function() {