Added manifest; added Get-NetBackupStatusCode

Added module manifest for easier versioning, etc. Also added the
Get-NetBackupStatusCode function, which wasn't in the 'to-do' for this
module, but is something that has been helpful in my organization for
quick & dirty troubleshooting.
modified CBH on Get-NetBackupStatusCode function
Merge pull request #1 from vN3rd/master

Added: Module Manifest; Get-NetBackupStatusCode