Organize the trading form into a template
Remove the empty currency options
Merge pull request #825 from stellar/trading-form-template

Trading form template
Disable send button when invalid, show summary
Confirm, sending, sent, and error states
Reuse the modalStatus classes
Merge pull request #830 from stellar/trading-form-overlay

Trading form modal statuses
Quick styling of buy/sell radio
Clean up, use dark grey, and look interactive