update travis, dependencies, and readme

.travis.yml

@@ -1,8 +1,13 @@
 language: node_js
-node_js:
-  - "0.10"
-  - "0.11"
-  - "0.12"
-  - "iojs"
-before_script:
-  - npm install -g grunt-cli
+sudo: false
+matrix:
+  include:
+    - node_js: '0.10'
+      before_install: npm -g i npm@2
+    - node_js: '0.12'
+      before_install: npm -g i npm@2
+    - node_js: '4'
+      before_install: npm -g i npm@2
+    - node_js: '4'
+      before_install: npm -g i npm@3
+