minui: Move callback functions to std::function.

Also make minor clean up to the header includes.

Test: mmma bootable/recovery system/core/healthd system/extra/slideshow
Change-Id: I3bfcf2c0e203c26a98ee08f1f8036c68356a69fd
diff --git a/minui/resources.cpp b/minui/resources.cpp
index e6909f2..9c69030 100644
--- a/minui/resources.cpp
+++ b/minui/resources.cpp
@@ -14,21 +14,19 @@
  * limitations under the License.
  */
 
+#include <fcntl.h>
+#include <linux/fb.h>
+#include <linux/kd.h>
+#include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
-
-#include <fcntl.h>
-#include <stdio.h>
-
 #include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sys/types.h>
-
-#include <linux/fb.h>
-#include <linux/kd.h>
+#include <unistd.h>
 
 #include <vector>
+
 #include <png.h>
 
 #include "minui/minui.h"