Merge pull request #183 from mlabs-haskell/gergely/version-bump

- Updated `cardano-wallet` to latest version (compatible with cardano-node 8.1.1)
- Updated nixpkgs, haskell.nix (moved to iog branch) , hackage.nix, iohk.nix

Merge pull request #148 from mlabs-haskell/adjust-collateral-creation

Update to BPI with adjusted collateral creation

Merge pull request #146 from mlabs-haskell/fix-docs

Minor docs fixes

fixed: awaitng of wallets to be fundeed

Merge pull request #141 from mlabs-haskell/experimental-config

Configurable slot length and epoch size

fixes for v1

configurable cluster MVP

Merge pull request #137 from mlabs-haskell/bug-adjust-unbalanced

Bugfix: adjusting unbalanced transaction

Merge pull request #129 from mlabs-haskell/master-docs-fixes

small docs fixes

Merge pull request #128 from mlabs-haskell/mitch/validity-error-check

`OutsideValidityIntervalUTxO` check