Okay so here is the example project.
the openFrameworks folder is included in the project folder because I had to comment out some FMOD related code to make it work.
the only other change that is needed is to modify freeimage.h
find the line:
typedef int32_t BOOL;
and change it to:
//typedef int32_t BOOL;
#define BOOL int32_t
Also a thing to note is that sometimes the system preferences doesn't re-load the screensaver correctly. so you have to right click on it in the list and remove it and then close system preferences and re-add it.
the screensaver can be found in Build/Debug/
I have not done anything yet in relation to the data/ folder that will come next.
Also be aware of the symbol clash issue described at the end here: http://cocoadevcentral.com/articles/000089.php
Basically it means you might not be able to have multiple screen savers with the same names / class names running at the same time.