It suddenly started crashing with an overflow getting the MRO of our
class that extends build_ext. No versions have changed other than cython
though, so I don't know why it crashed.

Log here: https://travis-ci.org/gevent/gevent/jobs/170750778

Simplify subprocess.py: Unify many py2/py3 branches

This adds the *timeout* and *input* arguments for Py2.

This required a small doctest renormalizer to handle the byte string
difference.

Fix test__makefile_ref under Windows 10 with new psutil 4.4 which actually started returning open files, not just connections.

Fix test__makefile_ref under Windows 10 with new psutil 4.4 which actually started returning open files, not just connections.

Also temporarily disable a bunch of travis/appveyor builds, I'm
expecting a bunch of commits on this branch.

Support for PyPy3

One more test that fails on Travis. Although we're getting lots of failures there now as it works to deal with the backlog of builds due to the DNS issues (we're timing sensitive).

These seem to be a mix of Py3.3 and newer tests.

Make them all "pass" by disabling as appropriate; almost all of them
were already disabled for either Python 2.7.8 (old SSL implementation)
or Python 3.4 (signal handling). I didn't see anything to be concerned
about.

Fixes #826.

Fix test__semaphore.py under PyPy3 by raising the right (wrong, really) exception type that PyPy does.

Add PyPy3 to travis config; disable most other builds for testing purposes for now. Still need to add PyPy3 specific tests.

Implement subprocess.run()

Make it available to all Python versions, not just 3.5. It is
cooperative on all versions.

This requires some minor updates to the Popen API (being a context
manager and having the args attribute on Python 2) and works best when
the TimeoutExpired exception is also defined in Python 2 (as a subclass
of Timeout, for BWC).

This prompts me to wonder if some of the duplicated Py2/Py3
methods (like check_call) can be combined now. I think I'm generally OK
with API extensions so long as there are no BWC concerns, and the
context-management, in particular, is nice for those methods.

Fixes #872.

* Fix #878

We can use multiple watchers to avoid any race conditions.

* Specific test cases for lines in os.waitpid.

* Less strict on the test since we may be running in parallel.

* make the leakchecker happy.

Support for and test Python 3.6

- Support encoding/errors args.
- Decode env items if necessary.
- Flush stdin during communicate.

Enable this test again on python 3 on travis.

It appears the gevent.signal module is not the source of the problem.

Also stop wrapping methods over and over. Yikes.