Handle server_hostname and _context in SSLv2 SSLSocket

With the backport of SNI code from Python 3 to Python 2.7.x, Python's
ssl.py is now passing server_hostname and _context into SSLv2's
SSLSocket, rather than just SSLv3's SSLSocket, so we need to handle
those arguments.

Remove extra backtick

Markdown typo correction

peek() should return the same element that get() returns, which
is not currently the case.

Add regression test for queue peek().

Fix broken link in the Introduction doc

- bugfix for error: ISO C90 forbids mixed declarations and code in libev...

made gevent.corecffi buildable under 32 bit systems

- mark test__os.py as flaky on python-dbg
- remove test_queue.py and test__threading_vs_settrace.py from FAILING

To prevent this:

======================================================================
FAIL: test_terminate (__main__.TestPool10)
----------------------------------------------------------------------

Traceback (most recent call last):

File "test__threadpool.py", line 176, in test_terminate

assert kill.elapsed < 0.5, kill.elapsed

AssertionError: 0.564028263092041

too slow

 * udp_client.py
 * gevent/subprocess.py

 * doctest