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.
If multiple header fields with the same name occur, they are combined
according to the rules in RFC 2616 sec 4.2:
Appending each subsequent field-value to the first, each separated by
a comma. The order in which header fields with the same field-name are
received is significant to the interpretation of the combined field
value.
Barry Warsaw
Tim Peters
Jeremy Hylton
Neal Norwitz
Skip Montanaro