new library messages

[Monte Goulding]

> On 17 May 2018, at 1:44 pm, Mark Wieder via use-livecode <use-livecode at lists.runrev.com> wrote:
> 
> Looking through some of the IDE's library stacks, I see handlers for the messages extensionInitialize and extensionFinalize. From the code in the handlers it seems that these are now standard ways to set up and tear down extension libraries, but I don't see the messages documented anywhere.
> Can I assume that the engine now issues these messages when extension libraries are loaded and unloaded?

No, they are called from the initialisation library.

> And that they should be a required part of extension library scripts?

Previously we had handlers `revLoadLibrary` and `revUnloadLibrary` but when Ali did the work for script libraries to be able to be packaged in a way similar to LCB extensions he renamed these to `extensionInitialize` and `extensionFinalize`.

Cheers

Monte