Ssh

* Ported over https://github.com/paramiko/paramiko/pull/63. Thanks to Dwayne
Litzenberger for catch & patch.
* 32: Raise a more useful error explaining which `known_hosts` key line was
problematic, when encountering `binascii` issues decoding known host keys.
Thanks to `thomasvs` for catch & patch.
* 33: Bring `ssh_config` parsing more in line with OpenSSH spec, re: order of
setting overrides by `Host` specifiers. Specifically, the overrides now go by
file order instead of automatically sorting by `Host` value length. In
addition, the first value found per config key (e.g. `Port`, `User` etc)
wins, instead of the last. Thanks to Jan Brauer for the contribution.
* 36: Support new server two-factor authentication option
(`RequiredAuthentications2`), at least re: combining key-based & password
auth. Thanks to Github user `bninja`.
* 11: When raising an exception for hosts not listed in
`known_hosts` (when `RejectPolicy` is in effect) the exception message was
confusing/vague. This has been improved somewhat. Thanks to Cal Leeming for
highlighting the issue.
* 40: Fixed up & expanded EINTR signal handling. Thanks to Douglas Turk.

* 15: Implemented parameter substitution in SSHConfig, matching the
implementation of `ssh_config(5)`. Thanks to Olle Lundberg for the patch.
* 24: Switch some internal type checking to use `isinstance` to help prevent
problems with client libraries using subclasses of builtin types. Thanks to
Alex Morega for the patch.
* [Fabric 562](https://github.com/fabric/fabric/issues/562): Agent forwarding
would error out (with `Authentication response too long`) or freeze, when more
than one remote connection to the local agent was active at the same time.
This has been fixed. Thanks to Steven McDonald for assisting in
troubleshooting/patching, and to GitHub user `lynxis` for providing the
final version of the patch.

* 5: Moved a `fcntl` import closer to where it's used to help avoid
`ImportError` problems on Windows platforms. Thanks to Jason Coombs for the
catch + suggested fix.
* 4: Updated implementation of WinPageant integration to work on 64-bit
Windows. Thanks again to Jason Coombs for the patch.

* Added an IO loop sleep() call to avoid needless CPU usage when agent
forwarding is in use.

* Handful of internal tweaks to version number storage.

* Updated `setup.py` with `==dev` install URL for `pip` users.