Support TEI XML P4 #1418
Description
The current TeiReader/TeiWriter are for TEI P5. In order to read data such the Old Baileys corpus, TEI P4 support would be good. Either the existing TeiReader could be made to support P5 and P4 at the same time (since of the currently supported elements apparently only the root element differs) or a new P4 reader/writer could be added.