Increment version to 2.60

Now that the upstream maintainer has abandoned this project without
establishing another maintainer, its difficult to choose an appropriate
version number. Going with 2.60 for now, as this only has incremental
changes to support 4B.

VERSION

@@ -1 +1 @@
-2.50
+2.60

version.h

@@ -1,3 +1,3 @@
-#define VERSION "2.50"
+#define VERSION "2.60"
 #define VERSION_MAJOR 2
-#define VERSION_MINOR 50
+#define VERSION_MINOR 60