app using ofxfluid added

i added a new app that uses ofxfluid to let people paint on the walls.

1) make sure you copy the "config" folder from other ofxOpenNi examples into bin/data/openni/
2) in header file, change the defines to make sure you have the right calibration file (if using one), and projector resolutions
3) in cpp file, switch the ofxSecondWindow to be full screen on extended screen (projector)"

     projector.setup("main", ofGetScreenWidth(), 0, PROJECTOR_RESOLUTION_X, PROJECTOR_RESOLUTION_Y, true);