README fix, plugin_path does not have a default (#95)
README fix, plugin_path does not have a default (#95)

* taste-tester: Update plugin_path info in README, markdown fixups

- The code has no default plugin_path, but README says it does; describe it as optional
- Add example plugin code snippet 
- Markdown fixes
- The plugin path really is a command line argument too, so show it has no default

jaymzh/taste-tester,facebook/taste-tester,facebook/taste-tester,jaymzh/taste-tester