fix version in packages

bower.json

 {
   "name": "gridstack",
-  "version": "0.2.6-dev",
+  "version": "0.2.6",
   "homepage": "https://github.com/troolee/gridstack.js",
   "authors": [
     "Pavel Reznikov <pashka.reznikov@gmail.com>"

package.json

 {
   "name": "gridstack",
-  "version": "0.2.6-dev",
+  "version": "0.2.6",
   "description": "gridstack.js is a jQuery plugin for widget layout",
   "main": "dist/gridstack.js",
   "repository": {