Remove support for 1.9.3 and 2.0.0
Remove support for 1.9.3 and 2.0.0

EOL for 1.9.3 was 23 Feb 2015
https://www.ruby-lang.org/en/news/2015/02/23/support-for-ruby-1-9-3-has-
ended/

EOL for 2.0.0 was 24 Feb 2016
https://www.ruby-lang.org/en/news/2016/02/24/support-plan-of-ruby-2-0-0-
and-2-1/

nationbuilder/nationbuilder-rb,nationbuilder/nationbuilder-rb