Make sure npm is updated in travis, and that unstable nodes, and old …

…(not the 2 latest stable) nodes, don't fail tests.

.travis.yml

@@ -2,7 +2,17 @@ language: node_js
 node_js:
   - "0.11"
   - "0.10"
+  - "0.9"
   - "0.8"
   - "0.6"
   - "0.4"
+before_install:
+  - '[ "${TRAVIS_NODE_VERSION}" == "0.6" ] || npm install -g npm@~1.4.6'
+matrix:
+  fast_finish: true
+  allow_failures:
+    - node_js: "0.11"
+    - node_js: "0.9"
+    - node_js: "0.6"
+    - node_js: "0.4"