Merge pull request #253 from FlowForwarding/multiple-instances

Multiple instances of LINC on Mininet
Handle reserved meter ids in ofp_meter_mod

Disallow creating and modifying meters with invalid meter ids.  Handle
delete requests with OFPM_ALL as meter id.

This closes FlowForwarding/LINC-Switch#158.
Merge pull request #254 from legoscia/meter_id

Handle reserved meter ids in ofp_meter_mod
Fix error message for port_mod to non-existent port

Return OFPET_PORT_MOD_FAILED + OFPPMFC_BAD_PORT instead of
OFPET_BAD_REQUEST + OFPBRC_BAD_PORT when the port number is valid but
the port doesn't exist.

Keep sending OFPET_BAD_REQUEST + OFPBRC_BAD_PORT for requests with
invalid or reserved port numbers.

This closes FlowForwarding/LINC-Switch#238.
Merge pull request #255 from legoscia/port-mod-error

Fix error message for port_mod to non-existent port
Remove debugging output

Motivated by #240.