Update json parsing with new PyLD library, serialization stays ad_hoc
json serialization : serialize only objects that are in the graph (label, ...)
Use rdflib n3 parser and not nt, removed label explicit serialization done by iter_other_arcs
Added attribute value for obsels created by simple-collector
Added PyLD as a requirement of the kTBS for json serialization
Json serialization for KtbsRoot, base, trace and obsels
Json : obsels can now be modified
ktbs: fixed JSON-LD serialization of models, and updated context accordingly
ktbs: fixed a bug in json-ld parser (and made it more robust)
ktbs: context can now be omitted in jsonld
ktbs: improved POSTing jsonld
Fixed regression in json parsing, being able make a PUT on KtbsRoot again
Small doc fix in Turtle tutorial, label is a skos:prefLabel
A few documentation updates
Begining of json parsing - serializing
moved jsonld support from plugin to default
Missing pyld import statement
ktbs: fixed by in serializing obsels in json-ld
additional fix for obsel json-ld serialization
rdfrest: minor fixes