New features:

E-mail notifications (on login, send, receive, logout)
Settings
Multiple languages (only action messages now)
Administrator interface
Client state block in dashboard
Meaningful messages (I found new ideas here!)
Auto suspend payouts on network fork
Withdraw address - if I encountered unsolvable problems, I can send your funds here when closing project.
API results in JSON format

What is not done yet:

Testing:

Screens

Client state block visible in dashboard tab:

'!' means error
'+' is incoming transaction
'-' is outgoing transaction
'?' is incoming, but not confirmed yet
API is global API state
Payouts is global payouts state
Client state is on when last connect was <300 seconds back. When off transactions will sent when client back online.

Settings tab (don't worry, I changed my API key):

Admin settings tab:

API in JSON format

Sample now:

$ curl -d 'api_key=xxx&method=get_balance' https://wallet.arikado.ru/api.php
{"balance":"6.21146789"}

And so on.