Deprecate elixir 1.3 so we can use split_with and no warnings on 1.6

.tool-versions

@@ -1,2 +1,2 @@
-elixir 1.5.2
+elixir 1.6.0-rc.0
 erlang 20.0

.travis.yml

@@ -1,17 +1,16 @@
 language: elixir
 elixir:
-  - 1.3.4
   - 1.4.5
-  - 1.5.2
+  - 1.5.3
   - 1.6.0-rc.0
 otp_release:
   - 18.3
   - 19.3
-  - 20.0
+  - 20.2
 matrix:
   exclude:
-    - elixir: 1.3.4
-      otp_release: 20.0
+    - elixir: 1.6.0-rc.0
+      otp_release: 18.3
 
 before_script:
   - MIX_ENV=test mix compile --warnings-as-errors

lib/benchee.ex

@@ -64,7 +64,7 @@ for {module, moduledoc} <- [{Benchee, elixir_doc}, {:benchee, erlang_doc}] do
     defp output_results(suite = %{configuration: %{formatters: formatters}}) do
       # Can be replaced with `split_with` once we deprecate elixir 1.3
       {parallelizable, serial} =
-        Enum.partition(formatters, &is_formatter_module?/1)
+        Enum.split_with(formatters, &is_formatter_module?/1)
 
       # why do we ignore this suite? It shouldn't be changed anyway.
       _suite = Formatter.parallel_output(suite, parallelizable)

mix.exs

@@ -7,7 +7,7 @@ defmodule Benchee.Mixfile do
     [
       app: :benchee,
       version: @version,
-      elixir: "~> 1.3",
+      elixir: "~> 1.4",
       elixirc_paths: elixirc_paths(Mix.env),
       consolidate_protocols: true,
       build_embedded: Mix.env == :prod,