Bump version for imminent 2.57b tag.

source/blender/blenkernel/BKE_blender.h

@@ -44,14 +44,14 @@ extern "C" {
  * and keep comment above the defines.
  * Use STRINGIFY() rather then defining with quotes */
 #define BLENDER_VERSION			257
-#define BLENDER_SUBVERSION		0
+#define BLENDER_SUBVERSION		1
 
 #define BLENDER_MINVERSION		250
 #define BLENDER_MINSUBVERSION	0
 
 /* used by packaging tools */
 		/* can be left blank, otherwise a,b,c... etc with no quotes */
-#define BLENDER_VERSION_CHAR	a
+#define BLENDER_VERSION_CHAR	b
 		/* alpha/beta/rc/release, docs use this */
 #define BLENDER_VERSION_CYCLE	release