travis: use Ruby 2.2
Rakefile: specify translation language in `Packnga::DocumentTask`
Remove unused variable
http thread: use POST for load command

GitHub: #2
Require groonga-command 1.0.8 or later
http coolio: use POST for load command

GitHub: fix #2
http: add synchronous backend

"thread" backend is implemented by synchronous backend.
http: set user-agent

"groonga-client/#{VERSION}" is used.
Add 0.0.9 entry
Bump version