loadUrl enhancements (#134)

`loadUrl` enhancements

- Make `options` parameter optional
- Allow partial overriding of instance options when calling `loadUrl` directly
- Make `requestOptions` optional
- Document `loadUrl` usage and provide examples

example/example.js

@@ -1,4 +1,31 @@
 /* global Pjax */
+var pjax;
+var initButtons = function() {
+  var buttons = document.querySelectorAll("button[data-manual-trigger]")
+
+  if (!buttons) {
+    return
+  }
+
+  // jshint -W083
+  for (var i = 0; i < buttons.length; i++) {
+    buttons[i].addEventListener("click", function(e) {
+      var el = e.currentTarget
+
+      if (el.getAttribute("data-manual-trigger-override") === "true") {
+        // Manually load URL with overridden Pjax instance options
+        pjax.loadUrl("/example/page2.html", {cacheBust: false})
+      }
+      else
+      {
+        // Manually load URL with current Pjax instance options
+        pjax.loadUrl("/example/page2.html")
+      }
+    })
+  }
+  // jshint +W083
+}
+
 console.log("Document initialized:", window.location.href)
 
 document.addEventListener("pjax:send", function() {
@@ -15,14 +42,20 @@ document.addEventListener("pjax:error", function() {
 
 document.addEventListener("pjax:success", function() {
   console.log("Event: pjax:success", arguments)
+
+  // Init page content
+  initButtons()
 })
 
 document.addEventListener("DOMContentLoaded", function() {
-  var pjax = new Pjax({
+  // Init Pjax instance
+  pjax = new Pjax({
     elements: [".js-Pjax"],
     selectors: [".body", "title"],
-    cacheBust: true,
-    // currentUrlFullReload: true,
+    cacheBust: true
   })
   console.log("Pjax initialized.", pjax)
+
+  // Init page content
+  initButtons()
 })