C++ implicit typedef.

Before I C++ify image, I'll C++ify bitvec.

It isn't even built in C++ yet.

src/image.hh

@@ -17,6 +17,7 @@
 /** @file
  * The DilloImage data-structure and methods */
 
+#include <memory>
 
 #ifdef __cplusplus
 extern "C" {
@@ -37,8 +38,6 @@ extern "C" {
  * Types
  */
 
-typedef struct _DilloImage DilloImage;
-
 typedef enum {
    DILLO_IMG_TYPE_INDEXED,
    DILLO_IMG_TYPE_RGB,
@@ -57,7 +56,7 @@ typedef enum {
    IMG_Abort       /**< Image transfer aborted */
 } ImageState;
 
-struct _DilloImage {
+struct DilloImage {
    void *layout, *img_rndr;
 
    /* Parameters as told by image data */