Improve development environment

[ghost]

1. Remove ruby 1.9.3 from supported rubies

   Ruby 1.9.3 is End of Life. I see no reason to officially support a ruby
   version which does not get any bugfixes from core developers.

2. Add support for JRuby 2 and 2.1 mode

3. Debugging

   pry seems to be the debugger-tool in the ruby-world. Together with byebug
   (ruby 2 only) even code walking is possible. The stack_explorer plugin gives
   you a nice access to the stack trace. The doc-plugin makes ruby doc available from within a pry session

4. License Finder

   aruba seems be used widely. So extra care should be taken with licensing
   issues. The license_finder helps
   you with that. It tracks license of all uses libraries. I whitelisted the MIT
   and the BSD-licenses, I think there's no problem here. I excluded the gems
   which are part of the development-group. They are not needed for the
   core-functionality.

@jarl-dk @mattwynne Feedback?

[mattwynne]

This is great. I suggest you update https://github.com/cucumber/aruba/blob/master/CONTRIBUTING.md to explain how to use the bootstrap and test scripts, then merge it in.

[mattwynne]

Thinking about it, I'm not sure why we need script/test - I think the default should be just to run bundle exec rake

[ghost]

There was a talk from a guy from github. Using script/* can be used in projects using different languages whereas bundle exec rake is ruby specific.

[ghost]

It's more a convience thing, that other developers do not need to think about running rake test or rake test:rspec or ... but hey there's a /script/test let's run this script to run tests.

[mattwynne]

OK well I don’t mind it. My fingers will always tend to run `rake` in a Ruby project in any case.

[ghost]

Rebased, added documentation and make use of the bootstrap script on travis to make sure it really works.

[mattwynne]

Go ahead and merge it then Dennis!

[ghost]

Access Denied.

[maxmeyer]

Ok. Done.

[mattwynne]

\o/