Update .travis.yml

Author: Trevoke

.travis.yml

@@ -1,10 +1,4 @@
 language: elixir
-elixir: 
-  - 1.0.5
-  - 1.4.3
-  - 1.6.0
-otp_release:
-  - 18.0
 cache: apt
 env:
   - EVM_EMACS=24.3 TEST_RUN="rake test"
@@ -13,6 +7,14 @@ env:
   - EVM_EMACS=25.1 TEST_RUN="rake test"
   - EVM_EMACS=25.2 TEST_RUN="rake test"
   - EVM_EMACS=git-snapshot TEST_RUN="rake test"
+matrix:
+  include:
+    - elixir: 1.0.5
+      otp_release: 17.4
+    - elixir: 1.4.3
+      otp_release: 18.0
+    - elixir: 1.6.0
+       otp_release: 20.1
 before_install:
   - curl -fsSkL https://gist.githubusercontent.com/tonini/09a8bec7a0b2c219e0d7/raw > travis.sh && source ./travis.sh
   - evm install emacs-$EVM_EMACS-travis --use --skip