added German i18n files
German translation by Zak Ryze
[#54] removed redundant API methods for sending coins
[#54] expect amount to be sent in satoshis
[#54] don't lock BTC amount unless it's set
[#54] various refactorings in HIAppRuntimeBridge
[#54] added helper constants for satoshi amounts
[#54] improved error handling in the API

- throw JS exceptions if required arguments are not given
- return null transaction data if transaction can't be found
- allow empty callback parameter in sendCoins
[#54] renamed some API methods

sendCoins -> sendMoney
getClientInfo -> getUserInfo