Fix spelling error in documentation
Update nav style
Add folder-select-directive.js
Rename directive & form partials for categories
Add backpack-show-controller.js; Refactor html
Rename backpack-controller to backpack-list-controller
Hide category select if user has no categories
Hide category select if user has no categories in form and items forms
Merge pull request #269 from theponti/feature/folder-directive

Feature/folder directive
Merge pull request #268 from theponti/development

Fix spelling error in documentation