TypeSystem: Small corrections in descriptions of 'Query.memEnds', 'Query.missEnds', 'Query.certEnds', 'Query.bestDist' and 'Query.bestQual'.
(duniter) gqlReceiver & distanceCalculations & events: three boolean constants ('GroupDisplayDuplicateError', 'GroupDisplayNotMemberError' and 'GroupDisplayUnknownError') introduced in gqlReceiver to avoid display of errors relative to groups (for paidge).
duniter/events: Adding "variables" into errors paths; adding type errors in scalar coercers.
duniterClient/parametersPrint: localisation of parameters comments ('name' as key).
util/graphQL: function 'coerceValue' changed to take into account the propagation of null values over non null types; adding type errors into scalar coercers.