Texture2D GetData and RenderTargets

GetData() likely was never used with rendertargets before, so the case had not been considered. Feel free to add the support. It’s a bit iffy function as for example on OpenGL2 ES it’s certain not to work.

EDIT: I’m checking this now too, if things go smoothly I may commit a fix today. Will verify OpenGL & D3D11 operation at the same time, and add a function to determine the amount of image components required to hold the data (see topic1112.html)

Should be fixed in the master branch now. D3D11 & OpenGL already worked.