Fix project description

The current project description is misleading, as it supports only draft 3 but not draft 4.

(Related to garycourt#73.)

README.md

@@ -4,7 +4,7 @@ JSV: JSON Schema Validator
 JSV is a JavaScript implementation of a extendable, fully compliant JSON Schema validator with the following features:
 
 *	The fastest extendable JSON validator available!
-*	Complete implementation of all current JSON Schema draft revisions.
+*	Complete implementation of all JSON Schema versions up to draft 3 (draft-zyp-json-schema-03).
 *	Supports creating individual environments (sandboxes) that validate using a particular schema specification.
 *	Provides an intuitive API for creating new validating schema attributes, or whole new custom schema schemas.
 *	Supports `self`, `full` and `describedby` hyper links.
@@ -208,4 +208,4 @@ Currently, the unit tests can not be run in Node.js.
 
 	The views and conclusions contained in the software and documentation are those of the
 	authors and should not be interpreted as representing official policies, either expressed
-	or implied, of Gary Court or the JSON Schema specification.
+	or implied, of Gary Court or the JSON Schema specification.