- Adds RedisAdapterTest::AlternateConfiguration to account
  for a relatively common alternative setup, as it’s used
  as the first example in the
  [Redis rubygem](https://github.com/redis/redis-rb#getting-started)

- Supplies original RedisAdapterTest with more complete
  redis:// url format by adding a ‘userinfo’ (blank user),
  so that it resembles the alternate configuration

- Supplies original EventedRedisAdapterTest with more complete
  redis:// url as well

- Adds before_script to start redis-server with password as a daemon
  and with explicit defaults copied from the default redis.conf
  (Instead of using Travis' default init/upstart scripts for `redis` service)