ERC20 Token support

The wallet now support multiple addresses and multiple tokens per single generated HD-key.

• Added support to send and receive ERC20 tokens
• Tokens look and feel like ether
• Added TokenChooser container to allow selection of desired tokens
• Added universal converter for exchange rates: convert from any token to any token!
• Added individual token list per network
• Added loading indicator during initial load
• Fixed problem with network menu on mobile