PR to support for skipping zeros for FixedVhd upload, Public IP, EndPoint ACL Rules and Specialized VM image.

I think [] is for specifying optional parameters. For required and positional we use '<>' angle brackets.
Look at the above cmd

```
 vm.command('create <dns-name> <image> [userName] [password]')
```
for the above command this means you can provide 4 parameters positionally.
The first two dns-name and image are required and the next two username and password are optional