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/common/icd-format.h b/icd/common/icd-format.h
index e628b1b..9c41700 100644
--- a/icd/common/icd-format.h
+++ b/icd/common/icd-format.h
@@ -105,6 +105,8 @@
 
 size_t icd_format_get_size(XGL_FORMAT format);
 
+XGL_IMAGE_FORMAT_CLASS icd_format_get_class(XGL_FORMAT format);
+
 unsigned int icd_format_get_channel_count(XGL_FORMAT format);
 
 void icd_format_get_raw_value(XGL_FORMAT format,