Duplicate Node Paths in Save File

Due to existing save format for nodes,
```
{"/node/path": {"attrs": {"attr1: {"value": "hello"}}}}
```
If there are multiple keys in the nodes dictionary that have the same path, during json load, only one is brought in.
In the current architecture, it should be impossible for the editor to produce these malformed save files, they can only appear due to hand editing or a bad git merge.