Rewrite of the main README.
HipPay example.
Ivory twitter handle.
Merge pull request #278 from ambiata/topic/readme

Rewrite of the main README.
Remove unused arguments to EavtTextImporter
Issue #283: Validate namespaces on ingest (before MR job)
Merge pull request #285 from ambiata/topic/ingest-invalid-namespaces

Validate namespaces on ingest (before MR job)
Issue #284: Extract cli repository handling and support IVORY_REPOSITORY env
Update README.md with IVORY_REPOSITORY