ignore other venv directories
put version number into sheepdog/__init__.py
Refactor out serialisation and add namespaces.

Serialisation all in sheepdog.serialisation now, and that file is included
in the generated job file.

Requests may now have a dict namespace for the function to run in.

Closes #1.
swap from os.getlogin to getpass.getuser

closes #7
Use ~/.sheepdog. Closes #6.
Actually allow the user to specify the path, see #6