Building Gadgets Version
buildinggadgets2-1.0.5
(bug encountered in Direwolf20 1.20 pack, v. 1.1.0)

Describe the bug
When pasting over an existing structure (such as when the copy/paste gadget runs out of power and stops mid-run), the gadget still expends power for the blocks that are already present, so it does not make any progress on subsequent pastes.

To Reproduce

1. Have a megastructure loaded into the copy/paste gadget ( When I encountered this, I was using https://www.reddit.com/r/9x9/comments/174wp23/futuristic_megabase_schematicupdated_to_1192works/ )
2. Paste the structure
3. The Copy/paste gadget runs out of power after pasting some portion of the structure
4. Paste the structure again from the same point -- so, overlapping the existing partially-built structure
5. The Copy/paste gadget runs out of power again, while making no progress

Expected behavior
The copy/paste gadget should not expend power for overlapping blocks that it does not need to paste