Standard Library support for generating a Globally Unique ID

This is a request to add a Standard library function to generate a Globally Unique ID on demand (maybe STD.System.Log.GenerateGloballyUniqueID).

This should make use of the same functionality that is available in the STD.System.Log functions (GetGlobalID/GetLocalID) when they need to generate a GUID when one already hasn't been provided in the HTTP headers for a given call, but should allow for the caller to request a new globally unique id on demand.

afishbeck