ofImage::setImageType doesn't alter the internal ofTexture if we need to about openframeworks

[kylemcdonald]

i think this issue needs to be reopened. it was hiding quietly, but while working w arturo on the floatpixels branch i added:

if(glInternalFormat != texData.glTypeInternal) {
    ofLogError() << "ofTexture::loadData() failed to upload internalFormat "... ;
}

and now i'm getting this error whenever i try to convert an image using setImageType.

i'm fixing this right now, but if you could re-open the issue i can close it when i'm done.