Add version and idl-version option
Make version generate script
Add template of version.ml
Add gitignore to ignore version.ml
fix invalid use of iterator in inverted_index_storage (fix #498)
Merge pull request #514 from unnonouno/jenerator-version

Jenerator version: #fix 466
Fix jenerator's gen_version script: refs #514
Fix regenerate for adding jenerator version

New jenerator become to put version of itself.
Merge branch 'develop' of github.com:jubatus/jubatus into develop