Tree pattern update

- Custom icons based on data attributes
- Make tree items button for tabbing
- Add ARIA support
- Remove blue highlights from opened folders in non-folder selection mode.
- Add carets to all folders that have children in both modes.
- Make all elements inline block instead of block for highlights due to CSS browser overflow bug
- Correct highlight and selected colors
- For folder select mode, folder and label in one element, caret in other. Caret opens folder while folder / label do not.
- For non-folder select mode, click on folder / label opens folder.
- 'Loading' text needs to be indented