Add's "avrispmkii" to the list of ISP's that don't have a port,
defaults to reading communication_type from avrdude.conf, which
is "usb" usually, rather than setting the -P flag which is the
user override.
Merge pull request #282 from sej7278/master

Add "avrispmkii" to the list of ISP's that don't have a port.

Fix #279