Add config to allow running FactoryGirl lint before suit

By default the lint will be run before every test suit.
Set it to false in config.yml if you would rather just use the rake
task: `bundle exec rake factory_girl:lint`

spec/support/factory_girl.rb

@@ -0,0 +1,7 @@
+RSpec.configure do |config|
+
+  config.before(:suite) do
+    FactoryGirl.lint if CONFIG['factory_girl_lint']
+  end
+
+end