Due to discrepancies in how command dispatchers receive datastore
options, especially after a "save" of the console, Boolean values are
stored as strings.
This is a quick fix for DisablePayloadHandler specifically, since it was
driving me insane.
this moves the following methods into common
arg_host_range ( used in creds and db )
arg_port_range ( used in creds and db )
set_rhosts_from_addrs ( used in creds and db )
show_options ( used in jobs and modules )