always use fail fast (in dev)

but not for the travis run (or test_all check)

test/helper.rb

@@ -14,7 +14,7 @@ end
 
 require "minitest/color"
 require "minitest/autorun"
-#require "minitest/fail_fast"
+require "minitest/fail_fast" unless ENV["TEST_ALL"]
 #require "minitest/reporters"
 #Minitest::Reporters.use! Minitest::Reporters::SpecReporter.new
 

test/test_all.rb

@@ -1,3 +1,4 @@
+ENV["TEST_ALL"] = "true"
 require_relative "helper"
 
 Dir["test/**/test_*.rb"].each { |f|