Drop Lexer::getPosition()

This was a leftover from the original column info implementation.

lib/PhpParser/Lexer.php

@@ -214,15 +214,6 @@ class Lexer
         return $this->tokens;
     }
 
-    /**
-     * Get's the current token-index (position in tokens).
-     * 
-     * @return int
-     */
-    public function getPosition() {
-        return $this->pos;
-    }
-
     /**
      * Handles __halt_compiler() by returning the text after it.
      *