Use the new Travis Docker infrastructure and stuff

.travis.yml

+sudo: false
+
 language: go
 
 go:
   - 1.2
   - 1.3
+  - 1.3
   - tip
 
 install: make updatedeps
+
 script:
   - GOMAXPROCS=2 make test
   #- go test -race ./...
 
+branches:
+  only:
+    - master
+
+notifications:
+  irc:
+    channels:
+      - "irc.freenode.org#packer-tool"
+    skip_join: true
+    use_notice: true
+
 matrix:
+  fast_finish: true
   allow_failures:
     - go: tip