Regular API function

Description	Combines two RGB images. See also sim.transformImage.
C synopsis
C parameters
C return value
Lua synopsis	string outImg=sim.combineRgbImages(string img1,table_2 img1Res,string img2,table_2 img2Res,number operation)
Lua parameters	img1: input image 1, as succession of rgb values. img1Res: x/y resolution of image 1. img2: input image 2, as succession of rgb values. img2Res: x/y resolution of image 2. operation: operation to be performed with the two input images.
Lua return values	output image as succession of rgb values.