fix spurious failures in test__socket_dns6.py
remove unused imports
pyflakes fixes
disable tests in test_httpserver failing on 2.6

only on travis:

test_authorization (__main__.CGIHTTPServerTestCase) ... Traceback (most recent call last):
    File "/usr/lib/python2.6/CGIHTTPServer.py", line 255, in run_cgi
      os.execve(scriptfile, args, os.environ)
  OSError: [Errno 13] Permission denied
  FAIL
  test_headers_and_content (__main__.CGIHTTPServerTestCase) ... Traceback (most recent call last):
    File "/usr/lib/python2.6/CGIHTTPServer.py", line 255, in run_cgi
      os.execve(scriptfile, args, os.environ)
  OSError: [Errno 13] Permission denied
  FAIL
  test_invaliduri (__main__.CGIHTTPServerTestCase) ... ok
  test_post (__main__.CGIHTTPServerTestCase) ... Traceback (most recent call last):
    File "/usr/lib/python2.6/CGIHTTPServer.py", line 255, in run_cgi
      os.execve(scriptfile, args, os.environ)
  OSError: [Errno 13] Permission denied
  FAIL

  ======================================================================
  FAIL: test_get (__main__.SimpleHTTPServerTestCase)
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File "test_httpservers.py", line 242, in test_get
    File "test_httpservers.py", line 218, in check_status_and_reason
  AssertionError: 200 != 404

  ======================================================================
  FAIL: test_authorization (__main__.CGIHTTPServerTestCase)
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File "test_httpservers.py", line 349, in test_authorization
  AssertionError: ('Hello World\n', 'text/html', 200) != ("Exception happened during processing of request from ('127.0.0.1', 60525)\n----------------------------------------\n", None, 200)

  ======================================================================
  FAIL: test_headers_and_content (__main__.CGIHTTPServerTestCase)
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File "test_httpservers.py", line 330, in test_headers_and_content
  AssertionError: ('Hello World\n', 'text/html', 200) != ("Exception happened during processing of request from ('127.0.0.1', 38970)\n----------------------------------------\n", None, 200)

  ======================================================================
  FAIL: test_post (__main__.CGIHTTPServerTestCase)
  ----------------------------------------------------------------------
  Traceback (most recent call last):
    File "test_httpservers.py", line 337, in test_post
  AssertionError: "Exception happened during processing of request from ('127.0.0.1', 45146)\n----------------------------------------\n" != '1, python, 123456\n'
os.py: do not import gevent.socket

since gevent.os is imported in __init__.py this makes gevent.socket imported in __init__.py which was never the intention.
subprocess.py: avoid reinitilization of rawlink()
fix syntax of xtest_signal.py on python2.6
upgrade libev to 4.15

This should fix #361.
ares.pyx: add 'cdef basestring'
Fix links for examples (docs gevent servers)
Port gevent vfd to win64

Since long on win64 is 32-bit it cannot hold all possible
SOCKET handle values, making it theoretically possible to
get an exception "OverflowError: Python int too large to
convert to C long" if socket handles become too big. Now
on win64 it properly uses PY_LONG_LONG.
new travis build

- do pep8 and pyflakes checks
- do not tests examples with dependencies (psycopg2_pool.py, web.py, geventsendfile.py)
- do check -dbg build
- install cython from ppa
- drop 2.5, add 3.3 (currently fails)

new make commands:
 - make whitespace
 - make pep8
 - make pyflakes
 - make lint       # runs all of the above
 - make travis     # runs on travis

The linters are run first to abort broken builds early.

Removed --full option to testrunner.py, it is no longer needed.
test___monkey_patching.py: don't fail if no tests are available for this version
Fix pep8
fix #423: pool: LoopExit in imap/imap_unordered

It was possible for IMap/IMapUnordered greenlets to exit without putting the final StopIteration. So, whoever was waiting on the results would have to wait forever (or until LoopExit if there's nothing else running in the program).

Original patch and test by @thinxer (close #424).

Fix #311: same issue.
Event: add dummy _reset_internal_locks
util.py: remove unused variable SLEEP
test__socket_dns.py: do not compare IPv6 addresses
core.ppyx: enable check watchers
disable test_urllib2net.OtherNetworkTest.test_ftp

too slow