ixia: Add support of LISTs in TRAFFIC

ixia: Add support of LISTs in TRAFFIC

The control script for Ixia (i.e. Ixia and IxNet classes)
is written in TCL and thus VSPERF must translate TRAFFIC
dictionary into TCL notation. The method for data type
conversion was updated to correctly process new 'capture'
settings, which uses python lists for tx and rx capture
ports definition.

JIRA: VSPERF-556

Change-Id: I639942b11ea11ce1b443a2a2e99c3da6619ba569
Signed-off-by: Martin Klozik <martinx.klozik@intel.com>
Reviewed-by: Al Morton <acmorton@att.com>
Reviewed-by: Christian Trautman <ctrautma@redhat.com>
Reviewed-by: Sridhar Rao <sridhar.rao@spirent.com>
Reviewed-by: Trevor Cooper <trevor.cooper@intel.com>
Reviewed-by: Richard Elias <richardx.elias@intel.com>