UUID cache

[RagnarGrootKoerkamp]

We could consider keeping a persistent cache that maps between UUIDs and shortnames.
Then when a person copies a problem tree, and updates things, we can detect that a new shortname is used for an existing UUID, and ask whether:

• This is indeed a fork of the problem, so keep the UUID
• This is a new problem, and update the UUID.

[mzuenni]

why not simply let the rename command also rename the cache?

[RagnarGrootKoerkamp]

The goal here is that if you copy an old problem as a starting point to develop a new one, we have a check that ensures you don't accidentally reuse the UUID.

[mzuenni]

ah never mind, misunderstood the issue ^^'