memory alloc: Add IMAGE and BUFFER alloc info structures

For images have the tests fill in the IMAGE_ALLOC structures.  For buffers
this is not yet done.

Conflicts:
	demos/cube.c
	demos/tri.c
	include/xgl.h
	tests/init.cpp
	tests/xgltestbinding.cpp
diff --git a/icd/intel/mem.c b/icd/intel/mem.c
index 47f312d..c2c31fe 100644
--- a/icd/intel/mem.c
+++ b/icd/intel/mem.c
@@ -34,6 +34,7 @@
 {
     struct intel_mem *mem;
 
+    /* ignore any IMAGE_INFO and BUFFER_INFO usage: they don't alter allocations */
     if ((info->alignment != 0) && (4096 % info->alignment))
         return XGL_ERROR_INVALID_ALIGNMENT;
     if (info->heapCount != 1 || info->pHeaps[0] != 0)