SYNTAX: PORK::blist_page_up([account])
	Moves a buddy list's cursor up one "screenful" down, if possible. A screenful here is defined as the number of buddy list lines that are visible on the buddy list's display.

INPUT PARAMETERS
	account: (Optional) The account whose buddy list will be affected. If this parameter is omitted, the account that's bound to the current window is assumed.

RETURN VALUE
	Returns 0 on success, -1 on failure.

SEE ALSO
	blist page_up
