Memcache cache adapter: in progress, completed Options and ResourceManager
Memcache adapter complete, passing tests
Fix MemcacheResourceManagerTest, updates from code review
Fix code style in MemcacheResourceManager
Updates/fixes from marc-mabe code review
Revert removed get multiple value internal methods; instead, remove set multiple value internal method
Determine memcache adapter capabilities based on stable or beta version
Force memcache delete 2nd arg to 0
Remove lib_options in favor of get/set compress threshold options
Merge pull request #5829 from cgmartin/memcache-adapter

Zend\Cache\Storage\Adapter\Memcache
[#5829] object calisthenics

- Promoted contents of several conditional statements, so that the bulk of the
  methods' work does not happen inside conditionals.
Merge branch 'feature/5829' into develop

Close #5829
Fixes #4481