test: remove golang 1.4 from build matrix for Travis

Signed-off-by: deadprogram <ron@hybridgroup.com>

.travis.yml

@@ -2,7 +2,6 @@ language: go
 sudo: true
 go_import_path: gobot.io/x/gobot
 go:
- - 1.4
  - 1.5
  - 1.6
  - 1.7
@@ -10,10 +9,9 @@ go:
  - tip
 matrix:
  allow_failures:
-   - go: tip
-   - go: 1.4
    - go: 1.5
    - go: 1.8beta1
+   - go: tip   
 before_install:
  - sudo add-apt-repository -y ppa:kubuntu-ppa/backports
  - sudo add-apt-repository -y ppa:zoogie/sdl2-snapshots