perf: replace some reduce with for (closes #46)

BREAKING CHANGE: begin work on legacy import ...

This also changes the name of the local storage keys for the master
password salt and tester, which means existing master passwords will
have to be set up again. Wallet storage should still be intact, as long
as the password is the same.

chore: update license information

feat: early work on address book

feat: add v2 backup import

fix: remove some debugging lines (closes #25)

feat: initial work on name transfer

feat: name picker

feat: save last tx from

refactor: master password hook

fix: allow empty string as category (fixes #8)

feat: broadcast wallet edits across tabs

feat: near completion with v1 backup importing

refactor: split up Wallet.ts

feat: backup results tree

feat: more backup import progress

refactor: import aliases

feat: auto-refreshing tables, optimisations

refactor: extract tx summary, fix redux, new hook

refactor: remove most unnecessary redux hooks

feat: block difficulty card

chore: update file headers

feat: support custom currencies

fix: sync node in redux

feat: sync balances with websocket

fix: minor add wallet improvements

feat: wallet editing

feat: wallet deletion

feat: show existing wallet categories

feat: sync new wallets when added

feat: wallet data syncing

feat: add wallets!

feat: hide advanced wallet formats

feat: add support for kw-username

feat: mostly finish wallet dialogs

feat: initial work on wallet dialogs

refactor: switch to ant-design

chore: tidy up some lint

refactor: forms in ModalDialog