Merge pull request #27 from y-higuchi/yoshi-master

Try ProtoBuf for IndexBlob
Merge pull request #28 from y-higuchi/yoshi-master

Copy to make vertex list in index modifiable
Merge pull request #29 from y-higuchi/yoshi-master

Check size
Merge branch 'master' of github.com:yoshitomo0912/blueprints-ramcloud-graph into yoshi-master