Do we keep copying the Solidity sources from raiden-contracts?

[pirapira]

Currently, contracts directory contains Solidity files that are copied from raiden-contracts. @LefterisJP pointed out that's weird. This issue keeps track of deciding what to do with the copied Solidity sources.

[pirapira]

@LefterisJP proposed to move the specification of contracts to raiden-contracts repo so we don't have to copy over the Solidity files in the spec repo.

[pirapira]

In the beginning we were saying that, if we come up with a better way, we can implement it: #204