remove patch level and test on 1.9.2
remove outdated gems

ref: https://github.com/guard/guard/commit/df14312317c29d5cc5d4f990b515f2aeabca89bb
Merge pull request #3 from sue445/refactor/readme

Readmeでの対応rubyバージョンの表記を変更
Merge pull request #4 from sue445/refactor/gemfile

Gemfileから不要なgemを削除
bundle update
Merge pull request #6 from sue445/refactor/bundle_update

bundle update