Constructor default name is confusing for blocks

When creating a constructor, the default name is `Constructor`. After adding this once, you end up with what initially looks like TWO blocks called `Constructor` in the toolbox: one to define a new constructor, and one for the constructor you've just defined.

One solution might be to leave the name as "Constructor" in the toolbox, but automatically rename even the first one to add a number (Constructor1) when it's placed in the workspace.

This is minor.