Using a simpler travis build matrix.

Author: h4cc

.travis.yml

@@ -1,19 +1,16 @@
 language: elixir
 sudo: false
 
-otp_release:
-  - 18.3
-  - 19.3
-  - 20.0
-  - 20.1
-  - 20.2
-  - 20.3
-
-elixir:
-  - 1.3
-  - 1.4
-  - 1.5
-  - 1.6
+matrix:
+  include:
+    - elixir: 1.3
+      otp_release: 18.3
+    - elixir: 1.4
+      otp_release: 19.3
+    - elixir: 1.5
+      otp_release: 20.3
+    - elixir: 1.6
+      otp_release: 20.3
 
 env:
   global: