Renamed file for avoiding name conflicts with other includes

The file shadow.h is likely to exist in multiple include folders; it now has been renamed to shadow-registry.h

inc-c/context.h

@@ -4,7 +4,7 @@
 
 #include <stdint.h>
 #include <shadow-tag.h>
-#include <shadow.h>
+#include <shadow-registry.h>
 
 typedef struct MtContext
 {

src-c/shadow-lookup.c

@@ -1,4 +1,4 @@
-#include <shadow.h>
+#include <shadow-registry.h>
 #include <context.h>
 #include <stdlib.h>
 #include <string.h>

src-c/shadow-pool.c

@@ -1,4 +1,4 @@
-#include <shadow.h>
+#include <shadow-registry.h>
 #include <stdlib.h>
 
 void mt_init_shadow_pool_allocation(MtShadowPool *pool)

src-c/shadow-registry.c

@@ -1,4 +1,4 @@
-#include <shadow.h>
+#include <shadow-registry.h>
 #include <string.h>
 #include <stdlib.h>