Implement command-based CLI, and start cluster-bringup

This change adds a CLI styled after the Go tool chain, with a design
inspired by that system. It adds 4 new commands, 'run',
'create-cluster', 'join-cluster', and 'version'. Full help is also
supplied.

Local-mode 'run' is fully functional, and 'create-cluster' also works.
One thing about `log.Fatal()` is that it dump a message to the shell if not configured. OK, that's fine. But it prefaces it will a timestamp. For something that is inherently a command that exits immediately, timestamp error reporting to the shell is a bit weird.
```
$ ./main 
2014/12/10 13:25:20 this is a fatal log message                                                                                                             
~/coding/go-log $ cat main.go                                                                                                                               
package main                                                                                                                                                
                                                                                                                                                            
import "log"                                                                                                                                                
                                                                                                                                                            
func main() {                                                                                                                                               
        log.Fatal("this is a fatal log message")                                                                                                            
}                                                                                                                                                           
~/coding/go-log $ ./main                                                                                                                                    
2014/12/10 13:26:53 this is a fatal log message
```
Or am I missing something?