Increments version to v0.5.6

This is solely a bugfix release, backporting the fix to #23 to the
v0.5.x release series.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "wirelesstags",
-  "version": "0.5.5",
+  "version": "0.5.6",
   "description": "Interface to the Wireless Sensor Tags platform (http://wirelesstag.net)",
   "main": "index.js",
   "scripts": {