LanguageMachines/libfolia: v2.11

[Ko vd Sloot] Significant refactoring, code cleaning, code reduction, and extra comments fixed memory leaks in the test (and also tests destroy() function now) Added some safeguards against multiple setnames for text_annotation. This is a limitation discussed in https://github.com/proycon/folia/issues/104 added code to handle text extraction for "empty" rows. implemented a fix for empty cell's. https://github.com/proycon/foliatools/issues/41 added a fix for text offsets in embedded elements in a structure that may NOT carry text itself. Like cell inside a table. [Maarten van Gompel] codemeta.json: updated metadata according to (proposed) CLARIAH requirement