function notClose(actual, expected, minDifference, message) {
    var actualDiff = Math.abs(actual - expected),
        result = actualDiff > minDifference,
        pushContext = _getPushContext(this);

    message = message || (actual + " should not be within " + minDifference + " (exclusive) of " + expected + (result ? "" : ". Actual: " + actualDiff));

	if (pushContext.pushResult) {
		pushContext.pushResult({
			"result": result,
			"actual": actual,
			"expected": expected,
			"message": message
		});
	} else {
		pushContext.push(result, actual, expected, message);
	}
  }
Checks that the first two arguments are numbers with differences greater than the specified
minimum difference.

@example assert.notClose(3.1, Math.PI, 0.001);

@param Number actual
@param Number expected
@param Number minDifference (the minimum exclusive difference allowed between the actual and expected numbers)
@param String message (optional)