Merge in ZHUB/z-push from develop to release/2.6

* commit 'b84efc59ad09b809427d46aea59b1d33271e12ee':
  ZP-1626 . SafeGetContents is now able to unserialize with opt param. Removed SafeGetContentsUnserialize not more needed. Released under the Affero GNU General Public License (AGPL) version 3.
  ZP-1626 . Re-added SafeGetContents. Released under the Affero GNU General Public License (AGPL) version 3.