redpen-302 Fix bug: SpaceBetweenAlphabeticalWordValidator
Merge pull request #307 from takahi-i/redpen-302

redpen-302 Fix bug: SpaceBetweenAlphabeticalWordValidator
redpen-286 Successive word validator

- added SuccessiveWordValidator class
- updated sample configs and documents to apply SuccessiveWordValidator
Merge pull request #309 from takahi-i/redpen-286

redpen-286 Successive word validator
Tiny fix (default configuration)