webpack config improvements

- new ‘debug-loader’ to help debugging webpack rules
- dynamically find and resolve all alfresco libraries

demo-shell-ng2/config/loaders/debug.js

@@ -0,0 +1,5 @@
+module.exports = function(source) {
+    this.cacheable();
+    console.log(this.resource);
+    return source;
+}