Add an option for pass/fail message

[markpatterson27]

Add fields that would allow for a feedback message to be given to learners based on whether the test passed or failed.

So test fields would be something like

{
    "name": "Test1",
    "setup": "",
    "run": "run Test",
    "input": "",
    "output": "pass",
    "comparison": "included",
    "timeout": 10,
    "points": 10,
    "passmessage": "Test 1 passed. Well done.",
    "failmessage": "Test 1 failed. Try checking your variable names."
}

[hardikshah197]

May I take this issue @markpatterson27 ? If it is not closed yet