alpha2:
  Changed some incorrect documentation (mainly that the
  argument being checked is the first argument to the
  <test>_usage_test function, NOT the last.

alpha3:
  Changed the function names to be more compatible with
  8 letter limits and autoload name clashes:
    _usage_test         becomes _test_usage
    _usage_display_string becomes _display_string_usage
    _usage_quoted_args  becomes _quoted_args_usage
    Type INTEGER becomes INT

alpha4:
   Fixed caller package support.
   Added type ANY
   Changed short name to add on LIST_OF_ for that prefix.
   Changed display of error to not include package name of function

beta1:
  Naming is now stable.

  Changed Test naming convention again! so that it supports
  8 character function name truncation better. As it was, if
  you want to support 8 character truncation, you need to 
  keep the test names below 6 characters. I've changed
  the names so that now it expects
  t_TEST_test_usage               instead of TEST_test_usage
  q_TEST_quoted_args_usage        instead of TEST_quoted_args_usage
  d_TEST_display_string_usage     instead of TEST_display_string_usage

  i.e, test functions have two characters prepended to
  allow the function names to be unique for the different parts
  of the test. Now tests cab be longer than 6 characters, they
  should still be unique under truncation to six characters though
  (if you think they may ever be used under DOS).
--------------------
  Added r_<test>_reference_arg_usage arg option to pass
  [$index,\@_] instead of $_[$index]. (see OPEN_HANDLE
  test for example of use)
--------------------
  Added tests INSTANCE, OBJECT, CLASS, OPEN_HANDLE (and supporting
  functions), and changed INT back to INTEGER, ANY to ANYTHING
--------------------
  Changed the calling stack so that _setUsage and _checkUsage
  are the ones which do the actual work - otherwise wrapping
  functions mixed up the stack depth. Now _setUsage and _checkUsage
  assume that they are called by ONE other function in Usage,
  which is in turn called by the function that is being tested
  in another package, that is in turn called from somewhere.

  i.e. the stack is always (from _setUsage and _checkUsage perspective)

  any function calling 'function'                 ((caller(3))[3])
  'function' calling 'Usage wrapper'              ((caller(2))[3])
  'Usage wrapper' calling _{set/check}Usage       ((caller(1))[3])
  _setUsage and _checkUsage                       ((caller(0))[3])

  This provides a consistent stack height for error messages.
--------------------
  renamed some private functions so that they were unique under
  8-character truncation.
--------------------
  Fixed error messages to be accurate about where the error occurred,
  including giving stack trace.
--------------------
  Added aliasing of tests
--------------------

beta2:
  Bug where INSTANCE, CLASS and OBJECT don't check for the given
  class, only superclasses!, is fixed - added function
   sub _classType {
      my($class,$ancestor) = @_;
      ($class eq $ancestor) || _has_superclass($class,$ancestor);
   }

  And changed all calls from _has_superclass to calls to _classType
  in INSTANCE, CLASS and OBJECT test functions.