Feature Request: implement version flag

[kbdharun]

➜  vib git:(master) ✗ vib -v
Error: unknown shorthand flag: 'v' in -v
Usage:
  vib [command]

Available Commands:
  build       Build the given recipe
  compile     Compile the given recipe
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  test        Test the given recipe

Flags:
  -h, --help   help for vib

Use "vib [command] --help" for more information about a command.

[deepu9]

@kbdharun I would like to work on it. Can you assign this issue to me. Thanks