Travis: Update Ruby versions in CI matrix

[olleolleolle]

This PR updates Ruby versions to latest releases in their series.

• jruby-1.7.27
• jruby-9.1.10.0
• 2.1.10
• 2.2.7
• 2.3.4
• 2.4.1 update! - added in this PR
• wrap rake ci in bundle exec - update and then making it "the default Travis task" (removing its specific configuration from the Travis YAML config)
• evict a Rake task file for rspec tests to the automatically available rakelib folder
• Rid the Gemfile of some duplication, making it shorter and easier to follow

[olleolleolle]

Proposal: Perhaps we could let go of 2.1?

[olleolleolle]

The current JRuby 1.7 build failure is about http_form's missing required_ruby_version in its .gemspec which does not preclude 1.9 Rubies from automatically using it.

It'd be nice if that gem had such metadata in its .gemspec.

[olleolleolle]

JRuby 1.7 is EOL'd, would it be more beneficial in the long run to hop over to JRuby 9.1.9.0?

[ixti]

@olleolleolle I'm sorry about that. Will fix form_data asap

[ixti]

@olleolleolle Can you please re-run tests. v1.0.3 of form data now fixed to play nice with jruby 1.7 and ruby 1.9+

[olleolleolle]

@ixti That fixed things here! Yes!

:hearts: :yellow_heart: :green_heart: :blue_heart: :purple_heart:

[olleolleolle]

@digitalextremist Is there anything more you'd like from this PR? Or, any change you'd like to see done to it?

[kenichi]

thank you - i think this is great as a specific PR, and i'm curious as to your thoughts about my other comments and what i've done to CI and deps in my own PR. i would be happy to revert/rebase from this!

.travis.yml Gemfile reel.gemspec

[olleolleolle]

@tarcieri I'm ready for code review on this one, now.

[olleolleolle]

@kenichi Oh, there we are, merged and good to go. Thank you for all of the input, it made this a lot better. Better is better!