Remove unused plugin
Fix indentation
Provide default resources to InvalidExpressionValidator
Fix formatting errors from checkstyle
Add license header
Refactoring InvalidExpressionValidator extracting ResourceLoader class
Enhance default invalid expression dcitonary
Changed the directory to store default resoruces
Merge pull request #199 from takahi-i/default-resource-for-invalid-expression

Default resource for invalid expression
Fix a bug repoted in #173
Refactoring SectionLengthVdalitor

- added getJoinedHeaderContents method in Section
- added tests to Section
Merge pull request #201 from takahi-i/fix-section-length-validator-bug

Fix a bug repoted in #173