Add support for pushing multiple values into a list.

Ruby allows you to push multiple values into an array via:

```ruby
array = []
values = [1,2,3]
array.push *values # => [1, 2, 3]
```

Redis also supports this with [`LPUSH`](http://redis.io/commands/lpush) and [`RPUSH`](http://redis.io/commands/rpush) as used here. But `redis-objects` has lacked support. This adds it.

Sorry for all the removals of whitespace. Sublime is set up to do that automatically on any file I save. I can fix it if it's an issue.