LanguageMachines/libfolia: v2.0

This is a major release. Supports the new FoLiA 2.0 features: provenance support more stricter checking on annotation declarations added the new TextMarkupReference class supports Hidden Words. All structure elements can have the 'space' attribute support for groupannotations many more. API and ABI breaches: library version bumped to version 10 many functions are renamed the text() functions have an ENUM parameter now to select for STRICT, RETAIN or HIDDEN bug fixes support for xlink: improved there as a rare mixup between nodes and nodes in the folia::Engine all nodes get a 't' attribute now on serializing. reading Extrenal FoLiA could get in an endless loop code refactoring and cleanu