Allow for global name import of the library.

Add enums to clean up any symbols from libssh2 and make interacting with them much easier to do.
Add additional unit tests for ParallelSSH#86

Author: Red-M

ssh2/__init__.py

@@ -1,3 +1,18 @@
 from ._version import get_versions
 __version__ = get_versions()['version']
 del get_versions
+
+from . import session
+from . import channel
+from . import sftp
+from . import exceptions
+from . import knownhost
+from . import agent
+from . import listener
+from . import pkey as privatekey
+from . import publickey
+from . import sftp_handle
+from . import fileinfo
+from . import statinfo
+from . import utils
+from . import libssh2_enums as enums