feat: update the version to 2.0.0 and restrict node version available…

… to 4.0

* Update the version to 2.0.0 and restrict node version available to 4.0

* Revert package.json version change
Remove minor versions of node on testing, only using major.
Remove version 5.0 from tests

.travis.yml

@@ -1,10 +1,9 @@
 sudo: false
 language: node_js
 node_js:
-  - "0.10"
-  - "0.12"
   - "4.0"
-  - "5.0"
+  - "6.0"
+  - "8.0"
   - "stable"
 
 # Make sure we have new NPM.

package.json

@@ -29,7 +29,7 @@
     "grunt-karma": "2.x",
     "grunt-npm": "0.0.2",
     "jasmine-core": "~2.4.1",
-    "karma": "1.x || ",
+    "karma": "2.x || ",
     "karma-chrome-launcher": "1.x || ~0.2.2",
     "karma-firefox-launcher": "1.x || ~0.1.7",
     "load-grunt-tasks": "^3.4.1"
@@ -38,6 +38,9 @@
     "jasmine-core": "*",
     "karma": "*"
   },
+  "engines": {
+    "node": ">= 4"
+  },
   "license": "MIT",
   "contributors": [
     "Maksim Ryzhikov <rv.maksim@gmail.com>",