Merge pull request #20 from tagawa/small-edits

Changed uglify setting for Grunt
Added initial files for Bootstrap 3
Added initial files for Bootstrap 3
Merge pull request #21 from tagawa/b3

Added initial files for Bootstrap 3
Added note about Bootstrap 3 version
Added note about Bootstrap 3 version
Merge pull request #22 from tagawa/docs

Docs
Changed element height calculation function for better collapsing
Merge pull request #24 from tagawa/b3

Changed element height calculation function for better collapsing
Added aria-expanded attributes
Merge pull request #25 from tagawa/accessibility

Added aria-expanded attributes
Fixed location of aria-expanded