feature(time): implement start property for profiling end and start times of messages

# Work in Progress

- [x] Implement API
- [ ] Implement ConsoleReporter to support timestamps
- [ ] Code Review

This branch is the beginnings of profiling...

```javascript
let end = logger.start.info('start some pretty hardcore work');
// All this crazy work.
end('woah, that was tiring.');
```

This would log out two messages from core: 

```javascript
// On first call
{
  level: 'info',
  group: 'feature',
  message: 'start some pretty hardcore work',
  timestamp: 1395002162444,
  guid: 1
}

// on end call
{
  level: 'info',
  group: 'feature',
  message: 'woah, that was tiring.',
  timestamp: 1395002162448,
  guid: 2,
  endOf: 1
}
```