New:
* Context rules and tagging (https://github.com/knaw-huc/golden-agents-htr#7): allows specifying regular-expression like patterns to match entities spanning multiple 'words'
* Allow choosing unicode codepoints for offsets instead of UTF-8 byte offsets (15)
Bugfixes:
* use lowest frequency of either variant or target when using variant lists (https://github.com/knaw-huc/golden-agents-htr#15)
* Allow out-of-vocabulary words in LM; not everything that's in the lexicons has to necessarily also in the LM