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
Merge pull request #26 from tagawa/small-edits

Fixed location of aria-expanded
Fixed Bower name
Moved event target code to a helper function
Merge pull request #29 from tagawa/small-edits

Moved event target code to a helper function
Updated docs for Bootstrap 3 improvements