Stop relying on the message text of ZeroDivisionError in tests.

The test for broken_repr relied on the message text of
ZeroDivisionError, which is different on pypy (just "integer
division", not "integer division or modulo"). This causes a test
failure. Fix this by explicitly raising an exception with a message we
provide.
Fix the 'processes' comment which is a bit misleading.

It says "number of processes to spawn", but what it does is enable
the SocketServer.ForkingMixIn which 'handles each request in a new process'.

Its value is not the number of processes but the maximum number of processes
that the ForkinMixIn will allow at the same time.
Adding Blackberry platform detection
Remove a duplicate line
Change the example in parse_options_header

This seems to be a more typical usage.
contrib.atom: Fix empty author tag bug in FeedEntry.

If no author is given, don't generate an empty author tag anymore.
Add support for the "category" element to feed entries

As per:
http://www.atomenabled.org/developers/syndication/atom-format-spec.php#element.category
Merge pull request #217 from agateau/atom-categories

Add support for the "category" element to feed entries
Merge pull request #211 from maix/master

contrib.atom: Fix empty author tag bug in FeedEntry.
contrib.atom: Fix copy and paste error in docstring.
Merge pull request #227 from maix/master

 contrib.atom: Fix copy and paste error in docstring
Merge pull request #208 from SimonSapin/patch-4

Change the example in parse_options_header
Merge pull request #202 from SimonSapin/patch-1

Remove a duplicate line
Fixed an error with openssl serving
Fix an error when using 'adhoc' as ssl_context
Merge pull request #198 from typingduck/master

Comment fix
Update docs for FileStorage
Remove docs reference to import_module
Merge pull request #200 from jessaustin/master

Add HTTPExceptions for 428, 429, and 431
Merge pull request #240 from vreon/patch-1

Remove docs reference to import_module