mp_image: change license to LGPL (almost)

Since michael was somewhat involved in it, wait with the actual license
change until the core is relicensed. Thus mark it as "Almost LGPL.".

The worrisome part about mp_image.c is that it was created by cehoyos
(which disagreed with LGPL) in commit f2dee32. But it turns out it
was a patch by someone else (who agreed with LGPL).

For some reason, the patch was actually slightly modified by cehoyos for
no reason (messed with the include statements), so we mess them back,
just to be sure.

Other than this, there were some commits that added support for new
IMGFMTs over the years. Some of these were by people we didn't ask or we
didn't get permission from. But since the original mp_image code was
replaced by more generic code using FFmpeg pixdesc, none of these
changes are left anyway.

One additional change by cehoyos (115bfb9) has been removed as well
(when "direct rendering" was dropped from the filter chain).

Copyright

@@ -299,7 +299,7 @@ LGPL relicensing status:
     video/image_writer.*            unknown
     video/img_format.*              hard
     video/img_fourcc.h              hard
-    video/mp_image.*                hard (if even possible)
+    video/mp_image.*                almost LGPL
     video/mp_image_pool.*           LGPL
     video/out/aspect.*              hard
     video/out/bitmap_packer.*       LGPL

video/mp_image.c

@@ -13,13 +13,10 @@
  *
  * You should have received a copy of the GNU General Public License along
  * with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Almost LGPL.
  */
 
-#include "config.h"
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
 #include <limits.h>
 #include <pthread.h>
 #include <assert.h>
@@ -33,7 +30,7 @@
 
 #include "mpv_talloc.h"
 
-#include "img_format.h"
+#include "common/common.h"
 #include "mp_image.h"
 #include "sws_utils.h"
 #include "fmt-conversion.h"

video/mp_image.h

@@ -13,6 +13,8 @@
  *
  * You should have received a copy of the GNU General Public License along
  * with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * Almost LGPL.
  */
 
 #ifndef MPLAYER_MP_IMAGE_H