version bump to 0.3.0 and added node >=0.6.0 dependency

Author: elbart

package.json

@@ -1,7 +1,7 @@
 {
   "name": "memcache",
   "description": "simple memcache client",
-  "version": "0.2.0",
+  "version": "0.3.0",
   "homepage": "https://github.com/elbart/node-memcache",
   "repository": "git://github.com/elbart/node-memcache.git",
   "author": "Tim Eggert <tim@elbart.com>",
@@ -18,7 +18,7 @@
     "test-cov": "make test-cov"
   },
   "engines": {
-    "node": "*"
+    "node": ">=0.6.0"
   },
   "keywords": [ "memcache", "memcached" ]
 }