[ANN] cascalog-elephantdb has moved to https://github.com/nathanmarz/elephantdb/elephantdb-cascalog

[Soren Macbeth]

The namespace was also changed from cascalog.elephantdb to elephantdb.cascalog.

Apologies for any inconvenience. The elephantdb codebase is currently evolving faster than cascalog so this simplified keeping everything in sync without forcing new cascalog releases.