updated travis to node v6

.travis.yml

@@ -1,24 +1,33 @@
 language: node_js
-# currently needed for some native builds on iojs 3
-addons:
-  apt:
-    sources:
-    - ubuntu-toolchain-r-test
-    packages:
-    - g++-4.8
+sudo: false
 node_js:
   - 0.10
   - 0.12
   - 4
-  - 5
+  - 6
 services:
   - redis-server
-  - mongodb
 script:
   - npm run coverage
-# currently needed for some native builds on iojs 3
-before_install:
-  - sudo update-alternatives --install /usr/bin/g++ g++ /usr/bin/g++-4.8 90
-  - g++ -v
 after_success:
   - npm run publish-coverage
+env:
+  global:
+    - CC=gcc-4.8
+    - CXX=g++-4.8
+    - MONGODB_VERSION="3.2.5"
+addons:
+  apt:
+    sources:
+      - ubuntu-toolchain-r-test
+    packages:
+      - gcc-4.8
+      - g++-4.8
+      - libzmq3-dev
+before_install:
+  - wget http://fastdl.mongodb.org/linux/mongodb-linux-x86_64-$MONGODB_VERSION.tgz
+  - tar xfz mongodb-linux-x86_64-$MONGODB_VERSION.tgz
+  - export PATH=`pwd`/mongodb-linux-x86_64-$MONGODB_VERSION/bin:$PATH
+  - mkdir -p data/db
+  - mongod --dbpath=data/db > /dev/null &
+  - sleep 5