Fix non-functioning wallet

[thomaseizinger]

I've started to fix the current non-working state as a result of the accidental merge of https://github.com/comit-network/waves/pull/202.

However, I am not going to continue because I want to focus on something else and hence just going to revert https://github.com/comit-network/waves/pull/202 for now given that it put master into a non-working state.

Whoever wants to pick https://github.com/comit-network/waves/pull/202 back up later can use these two patches as a starting point.