sw test tool: Enable parsing a new 'egress' format

The format is for throughput analysis.
sw test tool: Add support for deletion of flows for throughput analysis
sw test tool: Add support for installation of flows for throughput analysis
sw test tool: Add support for getting throughput
sw test tool: Enable throughput analysis
sw test tool: Add support for throughput analysis
sw test tool: Add default test files (meter)

These test files aim to examine 'meter instruction' of FlowMod message.