Get specs working

 * Add Travis testing for ruby 1.8 to 2.1
 * Update very old spec with new Spawn syntax
 * Update spec to rspec
 * Remove no longer needed rails dependencies from specs
 * Update Rakefile to use bundler/gem_tasks
 * Add coverage task for future coverage checking
 * Split initialize into run for test purposes
 * Define development dependencies explicitly in gemspec
 * Add Gemfile for testing