implement an API that's more harmonious with ichannel.

I think the shorthand methods for unix socket/redis are a step up from
one method with a large method signature(too many args) and it's also
in harmony with how ichannel spawns a unix socket/redis channel.
make IFuture.redis/unix the go-to for IFuture instances.
fix tests
require block in #initialize.
Merge commits.