New formatters

[tjayrush]

1. "appearance"
   • allows user to "Explore block" if she clicks on the block number (opens Etherscan to the block)
   • allows user to "Explore Tx" if she clicks on the transaction id (opens Etherscan to the tx)
   • does not show "link" color
   • example: transaction histories
   • create <AppearanceFormatter>
2. "function"
   • in history view if articulatedTx is non-null show the function name
   • current showing isArticulated
   • create <FunctionFormatter>
3. "tags"
   • on Names View, the tags column will be used as a filter. For now, just write to console.log
   • <TagFormatter>