Keep lemma translation for every form

Closes #478

This was not a bug per se - in fact it did exactly what I wanted it to
do, but probably under a false assumption. Every form stored their own
lemma translation, but as there is no visual link between them, this
appears to be counterintuitive.
Trigger a need for a save when gloss is updated
Translate Lemma Translation label
Fix french translation
Merge pull request #496 from latin-language-toolkit/lemma_trans_field

Keep lemma translation for every form
Fix path to jsondiffpatch bundle
Make cite definition more robust
Natively support constituents
Update retrievers for new sentence syntax
Temporary fix in language settings
Start conf file for Constituent demo
Start with ConstituentTreebankRetriever
First attempt at parsing morphology
Update jr config - use correct morph
Experiment with depTrees out of jr documents
Properly handle token ids in ConstTbRetriever
Track sentenceIds for constituents
Use an idMap for sentences as well
Take constituents out of sentences again
Introduce globalStore

This should be a place where retrievers (and plugins) can share data
with each other, that doesn't suit the tokens model of the general
system.

The first use case will be to save constituents. We could save them
sentence wise - but it leads to flexibility and sustainability issues,
as wider code changes would need to be taken into account to do this
every time we introduce a new concept.