ZF-4872: Add core support for Google Data protocol version 2

Description

Add core support for Google Data protocol version 2, including support for the final AtomPub specification as defined in RFC 5023.

Changes include:

  • Support for the new 'GData-Version' HTTP header.
  • New namespaces for AtomPub (app) and OpenSearch (openSearch) in version 2.
  • Support for using ETags to implement optimistic concurrency (ETag headers and gd:etag XML elements are recognized, and later used to set 'If-Match' HTTP headers).
  • Support for setting arbitrary headers on most HTTP-bound operations.

Comments

Marking as fixed for the 1.7 release.

Changing issues in preparation for the 1.7.0 release.