JsonLdError now inherits from StandardError instead of Exception
JsonLdError now inherits from StandardError instead of Exception

Signed-off-by: Aymeric Brisse <a462d6a602eb500679b027b39ff035d803cbe1e9@perfect-memory.com>

ruby-rdf/json-ld,PerfectMemory/json-ld,PerfectMemory/json-ld,gkellogg/json-ld,ruby-rdf/json-ld