Add py3.4 to .travis.yml
Add some missing documentation
Remove WebDAV from HTTP exceptions
Update news.txt
Removed link, replaced it with class link
Add exceptions documentation

This adds the exceptions as documentation for WebOb so that it can be
referenced in index.txt
Update HTTP Exception documentation
Use autoexception instead of autoclass
Merge pull request #173 from bertjwregeer/fix.documentation

Update the documentation for WebOb.exc
Merge branch 'travis-py34' of dairiki/webob into dairiki-travis-py34
also enable pypy3
Documentation states expires can be timedelta

The documentation for expires incorrectly states that expires can be a
timedelta, let's add a test for that.
Update documentation for set_cookie expires

The documentation erroneously states that that expires can be a
datetime.timedelta, this is incorrect, but since it has been documented
as such, we should continue accepting it.

Add the fact that it can be a datetime.datetime, and probably should be.
Cookies have names, not keys...
Refactor the respnse.set_cookie

Start using the make_cookie call that is available in webob.cookies,
this way we don't duplicate the same behavior.

There are a couple of backwards compatible fixes:

 - If expires is set to a timedelta, and max_age is not set, we set
   max_age to expires a timedelta

 - expires can also be a datetime, however this was not documented. So
   if it is a datetime, we want to get a timedelta, by taking the
   existing expires value, and removing datetime.utcnow() from the
   value.
Update the documentation for response.set_cookie max_age

We need to document that max_age can be an integer, timedelta or None,
and what that means.

max_age takes precedence over an expires argument.
Change test_cookies() to not include unicode

Unicode values in cookies are invalid.
Verify unicode values raise an exception
Update news.txt with latest fixes/documentation