Switch to using prospector for lint checks

Don't immediately run links added to an Event/AsyncResult while it is running callbacks. Fixes #771.

and document the settings.

Fixed typo error

Figured out the root cause of the u-v-a crash in https://github.com/PyCQA/pylint/issues/846: unsafe-load-any-extension causes it.

cleanup threadpool.
various small cleanups.
cleanup _fileobjectposix.

clean up resolver_ares
cleanup thread.
cleanup testrunner
cleanup pool.
clean up event

clean up socketcommon.
cleanup examples and servers.
cleanup server
cleanup util.
cleanup sslgte279
cleanup greentest.
cleanup corecffi.
cleanup fileobject.
cleanup select.py
cleanup socket2
fix naming.
cleanup socket3
cleanup hub.
cleanup threading.
cleanup lock
cleanup pywsgi.
cleanup _threading
cleanup patched_test_setup.

On travis, start a build with 2.7.8 so that _ssl2.py gets
tested (previously tested by Python 2.6). Do so with the test_ssl.py
from that version (because the changes are large), but keep using the
2.7.11 tests with just a few removals otherwise.

Drop support for python 2.6.

Move .pep8 to setup.cfg so it will be auto-detected.

Update c-ares to 1.11.0

- Replaced the whole directory with current source. This adds a few more
  scripts that we could remove again if desired, but it's easier just to
  be able to copy everything.
- However, the new test directory requires c++11, which travis doesn't
  have, so it's ditabled.
- The invocation of configure had to lose the CONFIG_FILES= param,
  because with that set, configure would fail to create the Makefile
  which in turn caused the whole thing to fail.

Test non-embedded versions of libev and c-ares

Downstream distributors like to use their system libraries for some
reason, so make sure that works, at least with the versions we have.
Previously at least one test was broken.

Fixes #759

On travis, start a build with 2.7.8 so that _ssl2.py gets
tested (previously tested by Python 2.6). Do so with the test_ssl.py
from that version (because the changes are large), but keep using the
2.7.11 tests with just a few removals otherwise.

Update tblib to 1.3.0

Update libev to 4.22