Adds link vertex get/set functions to the API

src/input2.c

@@ -7,7 +7,7 @@ Description:  reads and interprets network data from an EPANET input file
 Authors:      see AUTHORS
 Copyright:    see AUTHORS
 License:      see LICENSE
-Last Updated: 05/15/2019
+Last Updated: 10/29/2019
 ******************************************************************************
 */
 
@@ -330,11 +330,11 @@ int newline(Project *pr, int sect, char *line)
         case _TIMES:       return (timedata(pr));
         case _OPTIONS:     return (optiondata(pr));
         case _COORDS:      return (coordata(pr));
+        case _VERTICES:    return (vertexdata(pr));
 
         // Data in these sections are not used for any computations
         case _LABELS:
         case _TAGS:
-        case _VERTICES:
         case _BACKDROP:
           return (0);
     }