Fixes #2745.
Merge branch 'hotfix/2867' into develop

Forward port #2867
Adding hasUnknown and getUnknown methods to detect and get unknown inputs
Merge pull request #2873 branch 'hotfix/add-missing-throws-tags'
Merge pull request #2871 branch 'hotfix/change-logical-operator'
Memcached:
 - fixed some small issues on sharing memcached resources over different instances of Zend\Cache\Storage\Adapter\Memcached
   - implemented namespace support manually to not change Memcached::OPT_PREFIX_KEY on a memcached resource
   - added Zend\Cache\Storage\Adapter\MemcachedResourceManager that handles memcached resources
 - removed the default server configuration (127.0.0.1:11211)
 - added an option to create persistent connections "persistent_id"
Allow Zend\Db\Sql\TableIdentifier in getSqlString() too (not only in prepareStatement())
[Server] Reuse code from Zend\Code

Also remove underscore preffix from methods name
removed not needed use statement
Add unittests for new use of TableIdentifier in Sql\Insert, Sql\Update & Sql\Delete (Zend\Db)
fixed wrong doc-comment
Path for: add unittests for new use of TableIdentifier in Sql\Insert, Sql\Update & Sql\Delete (Zend\Db)
Merge branch 'feature/server-reflection' of git://github.com/Maks3w/zf2 into feature/server-refactor

Conflicts:
	library/Zend/Server/Reflection/AbstractFunction.php
[#2868] Fix some libxml test failures

- XmlRpc needed testing as it relies on Zend\Server\Reflection. Changes
  in recent versions of PHPUnit have made it more greedy with regards to
  warnings, which led to new test failures. The changes introduced make
  the component more resilient.
Merge branch 'feature/server-refactor' into develop

Close #2868
fix for extract behavior in collections plus test
see https://github.com/zendframework/zf2/pull/2848
fix for extract behavior in collections plus test
see https://github.com/zendframework/zf2/pull/2848
resolce merge conflict
removed debug code in test
Change-Id: Ifc71c8b7737c5d0bda9fd59d8811ca379f1d7799