Replace ZeroClipboard with clipboard.js

For copy/paste support in our code samples, we are using the
ZeroClipboard library which relies heavily on Flash.
Because many browsers/extensions are disabling this plugin nowadays,
this commit replaces ZeroClipboard with a native, lightweight solution
for this feature.

js/projectDocumentationWidget.js

@@ -107,9 +107,7 @@ Spring.SnippetView = Backbone.View.extend({
 
     var html = $(this.combinedTemplate(this.model));
     this.$el.html(html);
-    if (ZeroClipboard.detectFlashSupport()) {
-    	Spring.buildCopyButton(html.find(":first"), "snippet");
-    }
+    Spring.buildCopyButton(html.find(":first"), "snippet");
     return this;
   },