Stylize logs in 'fb start` command

I guess logs should be like 
`${taskName} | ${logLine1}`
`${taskName} | ${logLine2}`
etc.
For a more good viewing logs
For example
```
task1 | webpack start building...
task2 | styles has been builded
```
Will be good if concerning this issue in command `fb start` will have been added option `--show-time` or something like, for displaying time of log `task1 : 11:30 |  my log`