[wp-testers] WP_ENABLE_MULTISITE is now WP_ALLOW_MULTISITE

[Andrew Nacin]

WP_ENABLE_MULTISITE is now WP_ALLOW_MULTISITE. This is the constant
that turns on the Tools > Network menu. I think the new name will
minimize confusion with its purpose, as it doesnt actually enable
multisite itself, it just allows the Tools > Network install process
to occur.

So:
define('WP_ALLOW_MULTISITE', true):

The Tools > Network process has gotten a bit of a facelift in the past
week, and there's also some planned changes coming up. All could use
some testing and feedback.

Thanks testers!
Nacin