Don't associate with .0cc files on every single startup

[nyanpasu64]

Every single build of 0cc silently maps all .0cc files to itself, and Windows remaps it to the last known executable if you delete the .exe, preventing you from finding out.

CFamiTrackerApp::InitInstance()

Even if that behavior is only emailed for final-release builds, opening an older release in another path will override your associations.

Solution

• Only associate if .0CC has no association in registry.
• Add a button in Config to manually associate with current executable.