ci: drop io.js test

Because Node v4.0 has been released and edgy Node developers would
switch to it from io.js soon.

Author: shinnn

.travis.yml

@@ -3,7 +3,6 @@ git:
   depth: 2
 language: node_js
 node_js:
-  - iojs
   - node
   - '0.10'
 after_script: npm run cover

appveyor.yml

@@ -1,5 +1,4 @@
-init:
-  - git config --global core.autocrlf input
+init: git config --global core.autocrlf input
 
 shallow_clone: true
 
@@ -9,17 +8,15 @@ skip_tags: true
 
 environment:
   matrix:
-    - nodejs_version: '2'
+    - nodejs_version: '4'
     - nodejs_version: '0'
 
 install:
   - ps: Install-Product node $env:nodejs_version
   - npm install
 
-test_script:
-  - npm test
+test_script: npm test
 
 build: off
 
-cache:
-  - node_modules -> package.json
+cache: node_modules -> package.json