Bug? ofPixels allocates wrong amount of memory

[elliotwoods]

looking at:
https://github.com/openframeworks/openFrameworks/blob/master/libs/openFrameworks/graphics/ofPixels.cpp#L465

it seems that we always allocate the wrong amount of memory whenever PixelType != unsigned char since we're allocating an array of PixelType with array size being the desired size of memory in bytes (i.e. if PixelType is float, we're actually allocating 4* as much memory as we need).

perhaps instead we should be using pixels = new PixelType[pixelsSize];

[elliotwoods]

for reference pasting the function here:

template<typename PixelType>
void ofPixels_<PixelType>::allocate(size_t w, size_t h, ofPixelFormat format){
	if (w == 0 || h == 0 || format == OF_PIXELS_UNKNOWN) {
		return;
	}

	size_t newSize = bytesFromPixelFormat(w,h,format);
	size_t oldSize = getTotalBytes();
	//we check if we are already allocated at the right size
	if(bAllocated && newSize==oldSize){
		pixelFormat = format;
		width = w;
		height = h;
		return; //we don't need to allocate
	}

	//we do need to allocate, clear the data
	clear();

	pixelFormat	= format;
	width 		= w;
	height 		= h;

	pixelsSize = newSize / sizeof(PixelType);

	pixels = new PixelType[newSize];
	bAllocated = true;
	pixelsOwner = true;
}

[arturoc]

it should be new PixelType[pixelsSize] right? can you send a PR? otherwise i'll fix it later