VI Server reference lifetime strategies

[AndreaV-Lsi]

There are situations where you want to create refnums (i.e. notifiers and so on) within an Async Method. As it is implemented now as soon as an Async Method (called with the "Call and Collect" option) exits the VI Server reference is destroyed. The result is that all refnums created within the Async Method are destroyed as well and become invalid.

We need to implement different strategies for destroying VI Server references. Those strategies can be configured by a an enumeration with the following possible values:

1. "Destroy on Exit"
2. "Destroy on Actor Exit"
3. "Destroy on Application Exit"

Such enumeration is used as a property in the "Async Method" Message and can be set also in the "Async Method" Send method