Polish docs for HTML, Inflector, Language, Number, Path, Security and Smiley helpers

Also fixed a DB_cache bug introduced in previous commit and removed an unused parameter in a smiley helper
diff --git a/system/database/DB_cache.php b/system/database/DB_cache.php
index b8f8995..1be80c5 100644
--- a/system/database/DB_cache.php
+++ b/system/database/DB_cache.php
@@ -199,7 +199,7 @@
 	 */
 	public function delete_all()
 	{
-		delete_files($this->db->cachedir, TRUE, 0, TRUE);
+		delete_files($this->db->cachedir, TRUE, TRUE);
 	}
 
 }