!extend can now accept acorn level and level regulation requirements:
donguri=1/2
1 is the regulation level
2 is the BBS_ACORN value
For example:
`!extend:checked:checked:1000:1000:donguri=1/1`
it means `BBS_ACORN=1` and you must be level 1 to post
`!extend:checked:checked:1000:1000:donguri=4/2`
it means `BBS_ACORN=2` and you must be level 4 to post
