NGINX Ingress Controller 0.7.0

• 108: Support for the server_tokens directive via the annotation and in the configmap. Thanks to David Radcliffe.
• 103: Improve error reporting when NGINX fails to start.
• 100: Add the health check location. Thanks to Julian.
• 95: Fix the runtime.TypeAssertionError issue, which sometimes occurred when deleting resources. Thanks to Tang Le.
• 93: Fix overwriting of Secrets with the same name from different namespaces.
• 92: Add overwriting of the HSTS header. Previously, when HSTS was enabled, if a backend issued the HSTS header, the controller would add the second HSTS header. Now the controller overwrites the HSTS header, if a backend also issues it.
• 91:
  Fix the issue with single service Ingress resources without any Ingress rules: the controller didn't pick up any updates of the endpoints of the service of such an Ingress resource. Thanks to Tang Le.
• 88: Support for the proxy_hide_header and the proxy_pass_header directives via annotations and in the configmap. Thanks to Nico Schieder.
• 85: Add the configmap settings to support perfect forward secrecy. Thanks to Nico Schieder.
• 84: Secret retry: If a certificate Secret referenced in an Ingress object is not found,
  the Ingress controller will reject the Ingress object. but retries every 5s. Thanks to Nico Schieder.
• 81: Add configmap options to turn on the PROXY protocol. Thanks to Nico Schieder.
• Update NGINX version to 1.11.8.
• Documentation fixes: 104 and 97. Thanks to Ruilin Huang and Justin Garrison.