Add support for POST and new API to getPossibleValuesFromApi

[vemonet]

Improve getPossibleValuesFromApi:

• add support for POST queries if GET returns 405 method not allowed
• add support for APIs returning a direct JSONObject with the entity ID as key and its possible labels as array (e.g. http://robokop.renci.org:2434/docs)

Triggered only if searching for @id, uri and conceptid did not find anything

It will manage to resolve API returning the following JSON:

{
  "result1" : ["label 1", "label 2"], 
  "result2" : ["label 3", "label 4"]
}

Try it with the following template: http://localhost:37373/publish?1&template=http://purl.org/np/RAGEBhWnHEoCON2D539rwzyKDHwQjq8CeNOJo5e4fIL30

See it in action: