Upgrading dependencies (#280)

* upgrade yargs and async dependencies.

were breaking change, but no impact according the tests

* upgrade yargs and package-lock.json

* add node 8 to the tested versions

* add node 8 to the allowed failures as requested

* add node 9 to travis build as acceptable failure and remove node 7

.travis.yml

@@ -5,7 +5,8 @@ node_js:
   - "0.12"
   - "4"
   - "6"
-  - "7"
+  - "8"
+  - "9"
 
 script:
   - npm test
@@ -18,6 +19,7 @@ matrix:
   allow_failures:
     - node_js: "0.10"
     - node_js: "0.12"
+    - node_js: "9"
 
 notifications:
   email:

package.json

@@ -19,13 +19,13 @@
     "plugabble"
   ],
   "dependencies": {
-    "async": "^1.4.0",
+    "async": "^2.3.0",
     "ini": "^1.3.0",
     "secure-keys": "^1.0.0",
-    "yargs": "^3.19.0"
+    "yargs": "^10.0.3"
   },
   "devDependencies": {
-    "coveralls": "^2.11.4",
+    "coveralls": "^3.0.0",
     "eslint": "^4.9.0",
     "istanbul": "^0.4.1",
     "nconf-yaml": "^1.0.2",