Travis tests fail for ruby 2.0.0 for nokogiri >= 1.7.0

[ArturT]

nokogiri since 1.7.0 ended support for ruby 2.0.0.

https://github.com/sparklemotion/nokogiri/blob/master/CHANGELOG.md#170--2016-12-26

Example of failed build on travis:

https://travis-ci.org/mattheworiordan/capybara-screenshot/builds/217162971

Ideas how to solve the issue:

1) Ruby 2.0.0, for which official support ended on 2016-02-24. It means we could not test capybara-screenshot on ruby 2.0.0 at all.

2) Prepare separate gemfile just only to test it on ruby 2.0.0.

I would probably go with option 1).

[mattheworiordan]

@ArturT it's a tricky one that, we have these problems a lot for old versions. I am in favour of simply dropping 2.0 support given it's no longer supported.

[ArturT]

Sounds fine.