Fixes 22: Replace old AstComparer by the new and better DeepAstComparer
Added documentation about engine/parser AST nodes
Fixed RTD setters and getters to conform to the bean interface
Renamed WtTemplateParameter property "defaultValue" to "default" to match name as reported by getChildNames()
Added readResolve() method to WtEmpty* and WtNo* nodes to ensure correct deserialization
Added specialized equals() method to pairs of WtEmpty* and their Wt*Impl counterparts to make sure an empty Wt*Impl equals an WtEmpty*
Added WtComparer which is aware that WtEmpty* nodes sometimes equal their empty Wt*Impl counterparts and using it instead of old DeepAstComparer
Added missing hasTarget() to WtLinkOptionLinkTarget
WtEmptyNodeList is now a WtEmptyContentNode and no longer just a WtEmptyImmutableNode node
WikitextNodeFactory now extends ptk-common NodeFactory<WtNode>
EngineAstNodeConverter sets up a ptk-common AstNodeConverterBase<WtNode> for a wikitext AST
Using new ptk-xml-tools serializer