Update of3dGraphics_functions.markdown

Hi,
just trying to help expanding the documentation. I hope this helps.
Please note:
Not sure why but the following function gives error:
ofDrawPlane(&position, width, height)
e.g.
ofSetColor(0, 255, 0);
ofFill();
ofDrawPlane(ofPoint(ofGetWidth() * .5, ofGetHeight()* .5), 100, 200);

Error: No matching function for call to ofDrawPlane
(maybe I am doing something wrong and I cannot see it)
Using XCode 5.1.1 and oF 0.8.4

All the best
/Giuseppe