Fix opening ofp_channel and add starting conn_listener

OpenFLow 1.3.2 specification introduces a new statement that OpenFlow
controllers can connect to OpenFlow switches. After adjusting
the ofp_client API there is a need to fix openning the ofp_channel
in linc_logic. The module listening for connections from switches
is also added and started by linc_logic.
(FlowForwarding/LINC-Switch#147).
Implement reserved OFP port FLOOD

FLOOD port when used as an output port sends the packet out all standard
ports, but not the ingress port, nor ports that are in BLOCKED state
(OpenFlow spec. v1.3.2 ch. 4.5).
This behavior is required as NOX 1.3 controller uses this FLOOD port.
This commit should be reverted as soon as the issue
https://github.com/CPqD/nox13oflib/issues/3 is fixed.
(Motivated by #171).
Correct version in the example ofp_message records.  version = 4 means 1.3.2.
Merge pull request #188 from marcsugiyama/master

Correct version in the example ofp_message records
Add functionality allowing the controller connecting to a switch

OpenFLow 1.3.2 specification introduces a new statement that OpenFlow
controllers can connect to OpenFlow switches actively. Now
the of_controller_v4.sh can be started with an option simulating such
behavior.
(FlowForwarding/LINC-Switch#147).
Introduce config parameter for controllers listener; refactor linc_logic

OpenFLow 1.3.2 specification introduces a new statement that OpenFlow
controllers can connect to OpenFlow switches actively. Config parameter
`controllers_listener` is introduced to support this functionality.
By the way linc_logic module is refactored regarding this functionality.
(FlowForwarding/LINC-Switch#147).
Introduce checking if linc_logic process is alive between linc:start/stop

While running the tests it turned out that linc does not have enough
time to start. Now some checking is introduce to delay stopping the app.
(FlowForwarding/LINC-Switch#147).
Merge pull request #183 from FlowForwarding/issue171

Temporarily implement reserved OFP port FLOOD to support NOX 1.3 controller in Mininet environment
Merge pull request #187 from FlowForwarding/issue147

Support controllers actively connecting to the switch
Improve config_gen script after introducing new config parameter

New config parameter controllers_listener was introduce and the script
generating LNIC-Switch configuration needs to be modified.
(Motivated by #171).
Add description about running LINC with NOX controller in Mininet

Now LINC-Switch can connect to NOX 1.3 controller through the Mininet.
(Motivated by #171).
Merge pull request #190 from FlowForwarding/issue171

Update docs and config generation script regarding running LINC with NOX on Mininet
Fix starting the controller without command line parameters

It was impossible to start the controller without command line
parameters. Now it will start with default setting in such a case.
(Motivated by #147).
Merge pull request #193 from FlowForwarding/issue147

Fix starting the controller without command line parameters
Check group id before adding

Motivated by FlowForwarding/LINC-Switch#191.
Allow for sys.config file without controllers_listener parameter

For backward compatibility the controllers_listener parameter,
that decide whether active controllers can connect to the switch, should
not be require.
(Motivated by #147).
Merge pull request #195 from FlowForwarding/issue147

Allow for sys.config file without controllers_listener parameter
Delete flow entries when requested to delete flow tables

When receiving a table_features request that contains some but not all
existing flow tables, we should delete all flow entries in the absent
flow tables.
Add test scenario for issue #146
Merge pull request #192 from legoscia/table-features

Table features