Just a note of caution if you are using this. If you also have an add-in loaded with the same project name as the project name under test you may get an error about having a duplicate reference and the add-in under test won't load. You may continue to get this error even if you remove the duplicate projects/references, and even if you close and re-open the presentation file loading the add-in: it appears the reference is still retained even if it doesn't appear in the references list. The sequence of events looks like this:

* you get a duplicate name error when you run LoadAddin;
* you remove all possible sources of duplicate project names (closing files/removing add-ins/removing references);
* you still get the same error;
* you close the file (saving it) - and re-open it;
* you still get the same error;
* restart computer - error persists.

The only remedy seems to be to go to an earlier version of the file - saved before you tried to add the reference.