)
Call mail module entry point with:
	BX = function
	    0000h remove mail module
		Return: AX = status (0000h successful, else WEB error code)
	    0001h set mail poll
		Note:	schedules the WEB mail module
	    0002h set mail notify
		Note:	sets the Notify flag, which determines whether the
			  user will be notified when mail is received
	    0003h clear mail notify
		Note:	clears the Notify flag, which determines whether the
			  user will be notified when mail is received
	    0004h check whether new mail has arrived
		Return: AL = new mail status
			    00h no new mail since last call
			    else new mail has arrived
		Note:	also clears the new-mail flag after retrieving it
	    0005h send notify
		ES:DI -> name of WEB user to be notified
	    0006h get post office
		Return: ES:DI -> full network path of Post Office subdirectory