Add refuteEqual() as a synonym for assertNotEqual().
Rename ASUnit -> TestASUnit in test file.

Use ASUnit to refer to the library and TestASUnit
to refer to the top level of the test script.
Add assertInheritsFrom() and refuteInheritsFrom().
Fix the logic of assertInheritsFrom().
Add failIf() assertion.
Commit missing constant.
Add id property.

As os AS 2.3, this is required for library scripts.
See https://devforums.apple.com/thread/204960?tstart=0.
Add more tests.