Add settings array to connection parameters that executes SET statements once connected

app/Config/database.php.default

@@ -52,6 +52,12 @@
  *
  * unix_socket =>
  * For MySQL to connect via socket specify the `unix_socket` parameter instead of `host` and `port`
+ *
+ * settings =>
+ * Array of key/value pairs, on connection it executes SET statements for each pair
+ * For MySQL : http://dev.mysql.com/doc/refman/5.6/en/set-statement.html
+ * For Postgres : http://www.postgresql.org/docs/9.2/static/sql-set.html
+ * For Sql Server : http://msdn.microsoft.com/en-us/library/ms190356.aspx
  */
 class DATABASE_CONFIG {