Plugin test suite improvements
A range of minor improvements to the test suite, after trying it out with hardware (using the latest HERD proto-v0.4 API), including:
- Ability to run test suite using
python -m swatch.test_plugin
(plus corresponding plugin) - Merging 'link test' & 'algo test' config files for dummy plugin
- Link test FSM test: Don't compare captured data files with injected when using PRBS link operating mode