SQL file for upgrade

Failure allowed on:

• INSERT INTO but not INSERT IGNORE INTO.
• UPDATE IGNORE but not UPDATE.
• ALTER TABLE and ALTER IGNORE TABLE.
• DROP TABLE.

If a comment...

• begins with --- it is to be output, with a break only in debug mode. (and say successful\n\n if there was one before.)
• begins with ---# it is a debugging statement, no break - only shown at all in debug.
• is only ---#, it is "done." and then a break - only shown in debug.
• begins with ---{ it is a code block terminating at ---}.

Every block of code between "--- ..."s is a step. Every "---#" section represents a substep.

Replaces the following variables:

• {$boarddir}
• {$boardurl}
• {$db_prefix}
• {$db_collation}