Add chai-jquery, jquery plugins for Karma
Rename VisibilityToggler to Collapsable. Add button and screenreader label to trigger
TabSelector - restore test
Move i18nStrings to variable for readability
Collapsable - i18nStrings
Don't ignore bower.json itself

Ignoring bower.json prevents bower dependencies from being
picked up by applications dependent on this repo
Add ARIA properties
Shell stylesheet for Collapsable, required for frontend style guide to compile
Remove redundant attars property
Merge pull request #125 from moneyadviceservice/accessible-toggler

Collapsable component