Fixs ruby-1.8.7 travis build

Specify gem version (0.12) for celulloid on ruby 1.8.7 Gemfile
Removes unused dependencies

Celulloid wasn't the problem on broke ruby 1.8.7 build, after checking
Gemfile.lock jekyll is not being used and is requiring celulloid as dep,
so removing both

Removing google-api-client dependency too
Merge pull request #11 from fernandes/travis-ruby-1.8.7-passing

Fixs ruby-1.8.7 travis build