v0.9.4

Added

• cds: offer an optional flag --first-instance for --cds-upgrade-all that will cause all tenants to be processed by
  the first app instance only. this will make the upgrade less resource efficient, but resilient to auto-scaling.
  (fixes #104)

Fixed

• hdi: change internal logic to identify the relevant service both by offering name hana and plan name hdi-shared.
  this takes one more request, but it's much cleaner. before, we had implicitly assumed that no other service offering
  uses the plan name hdi-shared.