Adding delimiter for helper, documentation

Author: mattsah

README.md

@@ -67,6 +67,15 @@ $dot = dot();
 $dot = dot($array);
 ```
 
+It is possible use an alternative delimiter from the default dot (`.`) with the second constructor parameter.  Using an underscore instead:
+
+```php
+$dot = new \Adbar\Dot($array, '_');
+
+// With the helper
+$dot = dot($array, '_');
+```
+
 ## Methods
 
 Dot has the following methods:

src/helpers.php

@@ -11,13 +11,14 @@
 
 if (! function_exists('dot')) {
     /**
-     * Create a new Dot object with the given items
+     * Create a new Dot object with the given items and optional delimiter
      *
-     * @param  mixed $items
+     * @param  mixed  $items
+     * @param  string $delimiter
      * @return \Adbar\Dot
      */
-    function dot($items)
+    function dot($items, $delimiter = '.')
     {
-        return new Dot($items);
+        return new Dot($items, $delimiter);
     }
 }