cpp_redis::reply::as_double()

[whackashoe]

Looking to turn a reply into a double. cpp_redis::reply::as_double() doesn't seem to exist, I'm curious if this is intentional?

I think it'd make more sense for the reply class to support a redis_string which could be casted to std::string, int, float_t. The other types as list, set, hash, and zset could sit alongside the redis_string as types for the reply to cast to, while also using redis_string as type for k/v.