Add after-property to allow ordering of plugins

Some plugins do not depend on each other and can be used
independently, but if they are used at the same time, they have to
be executed in a specific order.

The "after"-property in components.js, allows the download page to
concatenate the plugins in the right order, without enforcing a
hard dependency.

components.js

@@ -606,6 +606,7 @@ var components = {
 		"keep-markup": {
 			"title": "Keep Markup",
 			"owner": "Golmote",
+			"after": "normalize-whitespace",
 			"noCSS": true
 		},
 		"command-line": {
@@ -616,6 +617,7 @@ var components = {
 		"normalize-whitespace": {
 			"title": "Normalize Whitespace",
 			"owner": "zeitgeist87",
+			"after": "unescaped-markup",
 			"noCSS": true
 		}
 	}

download.js

@@ -117,6 +117,7 @@ for (var category in components) {
 			noJS: all[id].noJS || all.meta.noJS,
 			enabled: checked,
 			require: $u.type(all[id].require) === 'string' ? [all[id].require] : all[id].require,
+			after: $u.type(all[id].after) === 'string' ? [all[id].after] : all[id].after,
 			owner: all[id].owner,
 			files: {
 				minified: {
@@ -374,18 +375,21 @@ function delayedGenerateCode(){
 	timerId = setTimeout(generateCode, 500);
 }
 
-function getSortedComponentsByRequirements(components){
-	var sorted = [];
-	for (var component in components) {
-		sorted.push(component);
+function getSortedComponents(components, requireName, sorted) {
+	if (!sorted) {
+		sorted = [];
+		for (var component in components) {
+			sorted.push(component);
+		}
 	}
+
 	var i = 0;
 	while (i < sorted.length) {
 		var id = sorted[i];
 		var indexOfRequirement = i;
 		var notNow = false;
-		for (var requirement in components[id].require) {
-			indexOfRequirement = sorted.indexOf(components[id].require[requirement]);
+		for (var requirement in components[id][requireName]) {
+			indexOfRequirement = sorted.indexOf(components[id][requireName][requirement]);
 			if (indexOfRequirement > i) {
 				notNow = true;
 				break;
@@ -403,6 +407,11 @@ function getSortedComponentsByRequirements(components){
 	return sorted;
 }
 
+function getSortedComponentsByRequirements(components){
+	var sorted = getSortedComponents(components, "after");
+	return getSortedComponents(components, "require", sorted);
+}
+
 function generateCode(){
 	var promises = [];
 	var redownload = {};