More work on #166:
 - Renamed `GroupComponent` to `GroupedInput`
 - Moved options before func, func is the last argument now, which is easier to compose
 - Added advanced group forwarding option: no forwarding, forwarding from specific port(s), forwarding from all ports
Updated CHANGES with `GroupedInput`
Merge pull request #181 from trustmaster/master

More work on #166: