testcase: scalability testcase enhancements

testcase: scalability testcase enhancements

Streams used by scalability testcases can be simulated
at different network layers by modification of destination
MAC address (L2), destination IP address (L3) or destination
UDP port (L4). It is possible to define number and type
of the streams by testcase definition by options "MultiStream"
and "Stream Type" or by CLI parameters "multistream" and
"stream_type". CLI options override testcase definition.
Number of streams, their types, used transport protocol
and indication of pre-installed flows are written to both
result CSV file and MD file with test report.
Default transport protocol was changed to UDP because
IxNetwork configuration script doesn't support TCP yet.

Change-Id: I1ff9ab7756d38f65b1a7730397507c5a5ff5a3d1
JIRA: VSPERF-81
JIRA: VSPERF-82
Signed-off-by: Martin Klozik <martinx.klozik@intel.com>
Reviewed-by: Maryam Tahhan <maryam.tahhan@intel.com>