Bump version to 0.21

CHANGELOG

@@ -102,3 +102,9 @@ Version 0.20, released August 18, 2012:
 	- Fix case-insensitive search for prefixes that contain invalid
 	  characters in their given case, but are valid if case-swapped
 	- Follow HTTP redirections in oclvanityminer
+
+Version 0.21, released August 21, 2012:
+	- Fix assertion failure in oclvanityminer work submission handler
+	- Fix bug in case-insensitive prefix enumerator that would skip the
+	  last possible combination.
+	- More useful error messages for OpenCL failures in oclvanitygen/miner

pattern.h

@@ -35,7 +35,7 @@
 #include <unistd.h>
 #endif
 
-#define VANITYGEN_VERSION "0.21pre"
+#define VANITYGEN_VERSION "0.21"
 
 typedef struct _vg_context_s vg_context_t;