refactor test harness

• refactor test harness into more discrete parts
• invoke Mocha using its main interface; move test suites to dedicated files
• structure tests using Mocha contexts
• encapsulate interaction with adapter in a manager object
• add a flight of tests that use the proposed ASG
• add support for configuration file per test
• allow location property to be optional
• print actual ASG if no expected ASG is found (for creating new tests)
• update sample adapter to conform to proposed ASG