Allow other apps to inject additional information at relevant locations via signals

[westonruter]

For example, given: /works/Bible.Tischendorf/tokens/2

The token object returned should include relevant information about the lemmas and morph parsings, things which are not part of the openscriptures_texts app. Therefore, the views outputting the token should have signals sprinkled throughout for the openscriptures_morphs app to insert the relevant information for the token.