Fix delta_5 query failing in newer MySQL version.

Newer MySQL versions in strict mode now does validation on DATETIME
fields to make sure that they're valid dates. This means that the
default value used and inserted by iPeer2, '0000-00-00', will fail
validation when we try to upgrade the database.

It's too late to fix this for delta_5, as it's already been released and
we should touch it as little as possible, but at least we can fix the
invalid dates in the 3.1 upgrade script. Luckily, we removed a lot of the
SysParameter entries and won't have to fix as many of them.
Schema better defaults, update sys version.

Increment the system.version in sys_parameters to the next release for
dev. Also changed some of the defaults in the user table as the original
NULL defaults were throwing errors with the update script.
Fix upgrader to run in iPeer v3, update db ver.

The upgrader was designed to upgrade iPeer v2 to v3, so it had problems
when I tried to run it in v3.

The upgrader was updating the system version but wasn't updating the
database version.

Also fixed spelling in upgrade's index.