Removed some hardcoded configuration.

Modified:
    - Composer, changed description.
    - AbstractRedis, Constructor now uses optional host, port and
        database parameters. Added some documentation.
    - RedisIgbinary, added unsubscribe(). Added optional constructor
        parameters.
    - RedisPubSubSerialize, Added documentation and optional
        constructor parameters.
    - Redis. newInstances uses new params.
    - RedisUnsubscribeException. No longer needs channel param,
        my implementation didnt work so I removed it.