Creates spec for RemoteFactoryGirl.create_list

Allows creating multiple resources with one method call.

Instead of doing:

```ruby
users = 1.upto(3).map |user|
  RemoteFactoryGirl.create(:user)
end
```

You can instead create 3 users like:

```ruby
users = RemoteFactoryGirl.create_list(:user, 3)
```
Adds implementation for RemoteFactoryGiril.create_list