[tokenizer] fixed handling of unparsed data in end(), added support for several states
[entities] added maps for normal & legacy entities
[tokenizer] added support for decoding HTML entities in `ontext` events

There is still a number of TODOs:
• support decoding entities in attributes
• when in XML mode, only decode XML entities (skip legacy entities)
• move the decodeMap to a JSON file
[tests] added test cases for decoding legacy & named entities

both containing one of the longest available entities, to ensure they
are propperly decoded (especially relevant for legacy entities)