Migrate from PyODM

PyODM continues to work fine for most use cases, but will no longer receive updates.

For new code, simply change your imports from pyodm to pyodx:

# from pyodm import Node
from pyodx import Node

We also renamed OdmError to GenericError:

# from pyodm.exceptions import OdmError
from pyodm.exceptions import GenericError

There are no other changes.