Merge branch 'develop'
Change defalut tokenize to TokenBigramSplitSmbol
Remove unnecessary index, and add columns to FileTable.
Separate diff into addition and deletion parts.
Copy test from gitlab/grit repository.
Replace module name Grit to Gifts::Grit.
Fix wrong diffs if b == nil
Replace GitRuby#diff to Git#diff.
Update test repos.
Fix test errors.
Add .travis.yml
Merge branch 'add-test'
Add travis link.
Set env TRAVIS=true
Fix error on travis.
Remove test repos/grit.
Update test repo.
Remove ruby v2.0.0.
Add refs of tags
Update .travis.yml