Update Podspec
Update README.md
Update README.jp.md
Update README.md
Update README.jp.md
Filters refactoring
Reimplement filter's serialization
Merge branch 'refs/heads/filters_refactoring' into development
Merge branch 'master' of github.com:CyberAgent/iOS-NBUKit into development
Commit pod files to Demo project to allow trying it even before installing Cocoapods

Related to issues #2 and #4