8chan fixes/additions

Added recaptcha option to create.php with separate config option to enable/disable it.
Added option to turn off AYAH on create.php page.

AYAH and Recaptcha are disabled by default on create.php because they require manual configuration to work.

Changed the way create.php checks if a username exists by sending a query for one username instead of grabbing all of the mods table and running them through a foreach loop. If the query doesn't return a username it doesn't exist.

Made it so you can't see every board(unindexed included) on the change password page unless you are a monerator/janitor/whatever. This is only for users who are ranked below admin.

Fixed install.sql, reports table was missing a boolean column called 'global'