<preparsecode> can be replaced by a "code" method

Signed-off-by: emanuele <emanuele45@gmail.com>
Even code blocks may have to rely on preparse blocks

Signed-off-by: emanuele <emanuele45@gmail.com>
Removed the <preparsecode> blocks from the xml for the MyBB 1.6 importer taking advantage of the new callMethod in the main loop

Signed-off-by: emanuele <emanuele45@gmail.com>