Issue with non english characters like german umlaut

[RudolfAchter]

When Creating or Setting Objects with New-nbObject or Set-nbObject you get JSON Encoding Errors. For Example whent you do something like this:

$nbVMObject= New-Object -Type PSObject -Property @{
	name="VMName"
	status="active"
	site="Datacenter in Brühl"
	cluster=1
	role=1
	vcpus=2
	memory=1024
	disk=10
	comments="Beschreibung für ein deusches System mit deutschn Umlauten äöüÄÖÜ"
}

New-nbVirtualMachine -Object $nbVMObject

[AnythingOverIP]

See #43