2to3: Apply `imports` fixer.

The `imports` fixer deals with the standard packages that have been
renamed, removed, or methods that have moved.

cPickle      -- removed, use pickle
commands     -- removed, getoutput, getstatusoutput moved to subprocess
urlparse     -- removed, urlparse moved to urllib.parse
cStringIO    -- removed, use StringIO or io.StringIO
copy_reg     -- renamed copyreg
_winreg      -- renamed winreg
ConfigParser -- renamed configparser
__builtin__  -- renamed builtins

In the case of `cPickle`, it is imported as `pickle` when python < 3 and
performance may be a consideration, but otherwise plain old `pickle` is
used.

Dealing with `StringIO` is a bit tricky. There is an `io.StringIO`
function in the `io` module, available since Python 2.6, but it expects
unicode whereas `StringIO.StringIO` expects ascii. The Python 3
equivalent is then `io.BytesIO`. What I have done here is used BytesIO
for anything that is emulating a file for testing purposes. That is more
explicit than using a redefined StringIO as was done before we dropped
support for Python 2.4 and 2.5.

Closes #3180.
BUG: Fix stray '.' in import statement.

There was a stray period at the end of an import statement in
`doc/cdoc/numpyfilter.py`. Looks like a cut and paste error that
was fixed elsewhere but escaped there because the module isn't
tested. A search shows that this was the only spot in which the
error was still present.
[BLD] Run 'full' test suite on Travis, including 'slow' tests

There's no reason *not* to run the full test suite on Travis, so long
as we fit in under the time limit. And no way to find out if we fit
under the time limit except to try ;-).
Merge pull request #3200 from njsmith/travis-full-tests

[BLD] Run 'full' test suite on Travis, including 'slow' tests
Merge pull request #3191 from charris/2to3-apply-imports-fixer

2to3: Apply `imports` fixer.
2to3: Apply `imports2` fixer.

No files were changed by this fixer, so add it to the list of
fixers to be skipped by 2to3.

Closes #3181.
MAINT: Append comma to last item tools/py3tool.py skipped fixers.

Makes it easier to put in the next fixer.
Merge pull request #3201 from charris/2to3-apply-imports2-fixer

2to3: Apply `imports2` fixer.