BUG Fix TreeMultiSelectField using the wrong label
BUG Fix encoding of selected title on TreeDropdownField
BUG Fix DataDifferencer trying to compare non-comparable fields (non-dbfield objects)
BUG: Fix issue with TreeMultiSelectField not saving
BUG: Fix issue with GridFieldPrintButton
ENHANCEMENT Instead of using multiple api calls to encode dbfield values, delegate this operation to the individual fields via forTemplate
Instead of using a new API to communicate html encoding to treeselect, just ensure all content is HTML encoded, and enable html_titles in jstree.
This is reverting templates back to pre-3.0 conventions,
which were dominated by XHTML templates.
HTML5 allows both self-closing and unclosed tags,
so opting for self-closing to achieve maximum compatibility.