Improved Messages for Routing Connections

Various improvements have been installed for routing connections.

In the column DT of the dialog Message management - <Project name> nothing was often displayed for connections in the past. Now the full DTs of source and target are displayed for connections in this column in round brackets (for example + (+A1-XD1:2 ↔ =GAA+A1-FC1:3)).
This applies to all connections.
The message 026042 "No entry point to routing path network found" was previously output after the routing without specifying a cause. Now the connection point for which no entry point was found is also named in the message.
If the source object for a message was deleted, this message still remained in the message management. In such a case nothing was displayed in the columns Page, DT, etc. and the Go to functionality did not work. Now the information "Message source does not exist anymore" is displayed in the DT column.
This also applies to connections, devices and other message classes.