Implemented implicit iterator pragma.

Fixed getPragmaOptions to return empty array if no options are set.
Fixed getVariable to return exact variable name matches before dot notation matches (i.e. the default iterator -- '.' -- will match the iterator and not try to do some crazy dot notation parsing.

examples/implicit_iterator/ImplicitIterator.php

@@ -0,0 +1,5 @@
+<?php
+
+class ImplicitIterator extends Mustache {
+	protected $data = array('Donkey Kong', 'Luigi', 'Mario', 'Peach', 'Yoshi');
+}