edge to string method (simplifies some other code fragments), and write color to the string

src/storm/storage/jani/Edge.cpp

@@ -151,6 +151,12 @@ namespace storm {
             destinations = newdestinations;
         }
 
+        std::string Edge::toString() const {
+            std::stringstream ss;
+            ss << *this;
+            return ss.str();
+        }
+
         std::shared_ptr<TemplateEdge> const& Edge::getTemplateEdge() {
             return templateEdge;
         }
@@ -181,6 +187,9 @@ namespace storm {
                 }
                 stream << "]";
             }
+            if (edge.getColor() != 0) {
+                stream << " color: " << edge.getColor();
+            }
             return stream;
         }
     }

src/storm/storage/jani/Edge.h

@@ -141,7 +141,8 @@ namespace storm {
              * If no assignment exists, this value is always zero
              */
             int64_t const& getHighestAssignmentLevel() const;
-            
+
+            std::string toString() const;
 
             void assertValid() const;