Introduce render.c and render.h which form the middle layer between
SDL and X and the remapper. One global remap_obj (hopefully a file scope
static later) is defined in render.c.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@618 7758b857-130e-0410-ab9c-d8735a528d18