core/segment.cpp: CDR3/JUNCTION, json output

Many people are used to have the full JUNCTION, including Cys104 and Phe118/Trp118.
We thus output both 'cdr3' and 'junction' fields in the json output.

algo/core/segment.cpp

@@ -1102,6 +1102,11 @@ json FineSegmenter::toJson(){
             {"aa", CDR3aa},
             {"productive", CDR3productive}
         };
+        seg["junction"] = {
+            {"start", JUNCTIONstart},
+            {"stop", JUNCTIONend},
+            {"aa", JUNCTIONaa}
+        };
     }
   }