Use the new Travis Docker infrastructure and stuff

.travis.yml

+sudo: false
+
 language: go
 
 go:
-    - 1.2
-    - 1.3
-    - tip
+  - 1.2
+  - 1.3
+  - 1.3
+  - tip
 
 install: make updatedeps
+
 script:
-    - GOMAXPROCS=2 make test
-    #- go test -race ./...
+  - 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:
-    allow_failures:
-        - go: tip
+  fast_finish: true
+  allow_failures:
+    - go: tip