client can now detect sftp connection close

Implments a clintConn.Wait() method.
Fixes: pkg#278

Thanks @wutzx for the PR.

fixes tests to run on windows

refactor opening files/dirs in request-server

Minor version bump due to a pretty heavy refactoring of the
request-server's handing of open packets. It now calls through to the
handler to initialize the reader/writer/lister objects when it receives
the open packet. This should be transparent and was done in relation to
a bug fix, but it is a pretty major refactor so the minor version bump.

Fixed pkg#280; Request.WithContext() deadlock when called from handler

Fix race issue in request server.

Fixes issue with lock/race condition in request server get/put.

bugfix release

fixes pkg#264; issue with rename in request example
fixes pkg#265; open/stat packet race condition (fixes sshfs as client)

Bugfix release.

Fixes pkg#260; packet ordering bug with ws-ftp client
Adds gcc-go AIX support.

New go module conformant version tag.

Fixes pkg#261

Bugfixes, docs and concurrent request option

- Fixes
     This created an unwanted C-go dependency.
     Plan to replace it with an callback/option.
Make sure to cancel context on requests with reader/writers that support
io.Closer.

- New features
Started improving documentation of Request based server.

new MkdirAll; fixes for fsetstat, attributes, list

Client.MkdirAll method mirroring os.MkdirAll
Fix pkg#243, flags and attributes not being set for fsetstat calls in
    request server
Fix pkg#245, request server attributes methods now use exported types
Fix pkg#240, fix issue with request server file list returning early

minor new feature (username/groupname lookup)

On Unix systems the server code will now attempt to lookup the username
and group name for the file longname value (used for ls -l output).