Fix manual layout when displaying subgraphs
Fix infinite loop on nonexistent dict key
Use new collections in DFS to speed up loading
Properly restart layout after adding/removing nodes to prevent layout bugs
Add Tic-Tac-Toe interaction

Closes #195.
Associate projects with UUIDs

Closes #200.
Merge pull request #206 from Muon/master

Dict infinite loop fix, Tic-Tac-Toe interaction, project UUIDs