Update Travis CI now that Active Record 4 is out
Require Ruby version 1.9.2 or later

This is because official support for Ruby 1.8.7 has been retired.
See http://www.ruby-lang.org/en/news/2013/06/30/we-retire-1-8-7/
Require tests to pass against Active Record 4.0
Update the documentation for Ruby version support
VERSION 0.7.0
Add spec for Github Issue #106
Remove spec dependency on will_paginate

This allows tests to pass for future Active Record versions on the Rails
git branches 4-0-stable and master
Handle Rails 4.1 change in DateTime precision

See https://github.com/rails/rails/commit/17f5d8e062909f1fcae25351834d8e89967b645e
Future-proof test for Active Record 4.1+
Add CHANGELOG entry for 0.2.2
Fix bad logic in Active Record version test in spec
Prefer double() to stub() for RSpec test doubles
Add workaround for loading JDBC adapter in JRuby
Add CONTRIBUTING.md
Convert README to Markdown from RDoc
Fix broken links in README
Prefer vanilla to Github-flavored markdown

That way, we get better syntax highlighting in yard, and therefore in rdoc.info

Unfortunately, we don't get syntax highlighting in Github anymore.
Update link to textacular
Add a link to the CONTRIBUTING guide
Fix broken link to text search trigger docs