Fix README

- changed the format from RST into Markdown
- changed the repository urls
Merge pull request #1 from takahi-i/fix-readme

Fix README
Fix the quickstart description
Merge pull request #2 from takahi-i/fix-quickstart

Fix the quickstart description
Add description on KatakanaEndHyphenValidator
Add description on Markdown syntax
Fix for comments
Merge pull request #4 from takahi-i/add-markdown-format

Add description on Markdown syntax
Merge pull request #3 from takahi-i/add-katakana-end-hyphen-validator

Add description on KatakanaEndHyphenValidator
Update setting file format and input format
Merge pull request #5 from takahi-i/update-format

Update setting file format and input format
Replace DocumentValidator into RedPen