Fs.sshfs

Added
- Support for passing arbitrary arguments to `paramiko.SSHClient.connect`
in `SSHFS.__init__` (paulgessinger [23](https://github.com/althonos/fs.sshfs/pull/17)).

Changed
- Bumped minimum required `fs` version to `v2.2.0`.

Fixed
- Explicitly register `SSHOpener` as an opener with `fs.opener.registry.install`
for cases where the `setuptools` metadata are unavailable and entry points
cannot be loaded.

Fixed
- Threading issue with `SSHFile` all sharing the same connection, causing
issues with code working on several files in parallel.
(willmcgugan [17](https://github.com/althonos/fs.sshfs/pull/17))
- `SSHFile` not being writable when opened in exclusive mode.

Changed
- Dropped support for Python 3.3 and Python 3.4.
- Bumped minimum required `fs` version to `v2.1.0`.
- Cache `SSHFS.locale` and `SSHFS.platform` properties using `cached-property`.
- `SSHFS` now uses the `timeout` argument it received on initialization when
running an arbitrary command on the remote server.

Fixed
- Catch all exceptions and not just `FSError` in `SSHOpener`.

Changed
- Make `SSHFile` transfers to be pipelined by default to increase performance.

Changed
- Use `$LANG` instead of `locale` to guess the locale on the remote server.

Fixed
- `SSHOpener` not using the `create` argument properly.

Fixed
- License file not being packed in source distributions
(dougalsutherland [8](https://github.com/althonos/fs.sshfs/pull/8))