Replace Merkle trees with lists

[pirapira]

following the recent change to the contracts
raiden-network/raiden-contracts#1062

[LefterisJP]

Why do we have the contract sources duplicated in the spec?

[pirapira]

@LefterisJP for generating API docs.

[LefterisJP]

So for this page? https://raiden-network-specification.readthedocs.io/en/latest/smart_contracts.html

I know it's a big change and not something to focus on now but perhaps it would make sense to have the raiden-contracts repo generate their own documentation and simply link to it at the contracts section of raiden spec if it's like this. Duplicating the contracts code all the time is just error prone.

[pirapira]

@LefterisJP I think that's a reasonalbe solution but it's for the team to decide: #235

[czepluch]

Please address my questions. I just have one thing that I am uncertain about. Other than that it looks good and will approve when you have clarified. Thanks!

[czepluch]

Thanks a lot for the changes. Looks good to me.