Fixed Duplicate and Input nodes creating objects only once in a for-loop

[tomoaki-e33]

Example node tree:

Result in v3.1.4:

Result after this PR:

[aachman98]

I really like how you handled the object creation when the node is re-executed, but I think there might be an easier workaround.
Consider the following steps:

1. Create an object: bpy.ops.mesh.primitive_something_add(something)
2. Go to edit mode
3. Use same function used in Step 1 to append geometry into same object without creating a separate mesh.

So instead of manually keeping record of all the objects generated, it would be better to create additional set of nodes that call bpy.ops.mesh, but in Edit Mode of the input object. The class "ScEditOperatorNode" would be the parent class for those nodes (rather than "ScInputNode").

We can think of something similar for "Duplicate Object" node.

[aachman98]

We'll have to add a prefix to the current input nodes, like "Create Cube".
Then we can have edit operator nodes like "Add Cube", but keep them in the "Inputs" category.