use memcached gem

memcache-client is already deprecated
https://github.com/mperham/memcache-client#memcache-client-is-deprecated-as-of-august-2010--it-will-be-supported-through-2010-but-new-code-should-use-dalli-instead
if can not connect memcached, skip memcache with memcached server tests
if can not connect redis, skip redis with redis server tests
divide skip cause for Mongo test

- cause 1 : Mongo lib LoadError
- cause 2 : can not connect to Mongo server
skip redis test of redis not available
Merge branch 'bash0C7-skip-padrino-cache-test-if-can-not-connect-to-cache-server'

Conflicts:
	padrino-cache/test/test_stores.rb
update CHANGES
Merge remote-tracking branch 'upstream/master' into super-admin

* upstream/master:
  update CHANGES
  skip redis test of redis not available
  divide skip cause for Mongo test
  if can not connect redis, skip redis with redis server tests
  if can not connect memcached, skip memcache with memcached server tests
  use memcached gem