bump to v0.4.0 (openethereum#499)

Merge pull request openethereum#370 from paritytech/luke-misc-thibaut

Change Cancel to Back button. Password field autofocus on Unlock component

Merge pull request openethereum#259 from paritytech/am-fix-ci-2

Add default case

Merge pull request openethereum#241 from paritytech/ac-update-deps

Update @parity/electron dependency (fix openethereum#240)

Merge pull request openethereum#230 from paritytech/am-fix-confirmations

Fix bug confirmations not working with latest light.js

Merge pull request openethereum#200 from paritytech/Tbaut-patch-readme

Update README.md

Merge pull request openethereum#139 from paritytech/am-fix-form

Fix form

Merge pull request openethereum#135 from paritytech/am-form-validation

Form validation