Header files for boosting

Header files for a general boosting framework. 
I might need a refresher on how threads in OpenBR work (besides magically). I wrote it like this because I didn't want to have the load the model file every time the transform was called in parallel, which is why I went with the br::Resource although apparently that doesn't work the way I thought it did either. Ultimately, my goal was to have one instance of a cascade that multiple threads can call Cascade->detect() from. Perhaps I should instead be asking how can I make that happen and is that the best way to do this :)