Add mix.scripts() and mix.styles() aliases.

These are identical to mix.combine() in every way. I’m adding them for
readability and legacy purposes (for folks switching over from Laravel
Elixir).

src/index.js

@@ -204,6 +204,28 @@ module.exports.combine = (src, output) => {
 };
 
 
+/**
+ * Alias for mix.combine().
+ *
+ * @param {string|Array} src
+ * @param {string}       output
+ */
+module.exports.scripts = (src, output) => {
+    return module.exports.combine(src, output);
+};
+
+
+/**
+ * Alias for mix.combine().
+ *
+ * @param {string|Array} src
+ * @param {string}       output
+ */
+module.exports.styles = (src, output) => {
+    return module.exports.combine(src, output);
+};
+
+
 /**
  * Identical to mix.combine(), but includes Babel compilation.
  *