imports of test modules now import from the test package.  Other
related oddities are also fixed (like DeprecationWarning filters that
weren't specifying the full import part, etc.).  Also did a general
code cleanup to remove all "from test.test_support import *"'s.  Other
from...import *'s weren't changed.

In README:  Write up (Guido's) rules for intra-test imports; warn against
asserts; document test_support.use_large_resources.

This is done for backward compatibility with Python 1.4.

portable output.

triggering a bogus TestFailed exception.

tests.

found.

(testall.out): obsolete.  see individual test output files in the
Output directory.

(testall.py): now contains only the list of all tests

(autotest.py): The new testing harness.  Supports -g option to
generate output files instead of verifying; -w option to warn about
non-tested optional modules; additional command line arguments to
generate or test individual tests (useful for generating output file
of new tests).

  constructors.  There is no backward compatibility.  Not everything has
  been tested.
* aiff.{py,doc}: deleted in favor of aifc.py (which contains its docs as
  comments)

(testing operations on built-in types) and autotest.py (automatic
regression testing).