#181 Tree of object entities in GUI should automatically select newly created entity.

[Shou Matsumoto]

This is just an usability issue.

If we are creating a new object entity in the JTree of object entities (see GUI), we shall select an existing object entity (let's call this a "parent" object entity), and then the software will create a new object entity as its child (i.e. below the "parent," in the hierarchy).

It will automatically create an entity with some name like EX2 or EX3 and so on, so it's natural to think that users will rename the newly created entities immediately.

However, after creating a new object entity, the GUI keeps the selection still pointed to the parent, so we need to click at the newly selected object entity and then change its name in a text field and then commit.

This makes the GUI less usable, because we cannot do something like: select the parent entity, add a new object entity, change the name, and press enter.
Instead, we should do something like: select the parent, add a new object entity, select the newly created entity, change its name, and then press enter.

So, it would be better if the JTree selects the newly created entity by default, instead of keeping the selection still pointing to the parent entity.