v2.28.0

• [Added] New extension ext-multi (experimental).
• [Added] ext-dnd5 support for dragging multiple selected nodes.
• [Added] #830 support for Font Awesome 5 (ext-glyph preset).
• [Added] ext-glyph supports SVG icons.
• [Added] icon option supports {html: "..."} content (also available for glyph-ext mapping).
• [Added] New method tree.visitRows()
• [Added] New method tree.selectAll()
• [Added] New method node.isBelowOf()
• [Added] New extension ext-fixed (experimental).
• [Changed] Re-rename clearData() to clearPersistData()
• [Changed] #828 Re-scale debugLevel from 0:quiet to 4:verbose, allowing to suppress warnings
  and even errors.
• [Added] CSS helper classes:
  
  .fancytree-helper-disabled

.fancytree-helper-hidden (replaces ui-helper-hidden)
  
  .fancytree-helper-indeterminate-cb

fancytree-helper-spin for icon animations (replaces glyphicon-spin)
• [Fixed] #819: ext-filter: Handle nodes without title.
• [Fixed] #835: ext-dnd5: Accept drop externals after drag.

Commit details.