Previously, it was possible for an object to be "refreshed" with a stale cached state from the current thread's context.
This ensures a check against the database is performed as well.
Resolves#1562.
Some .osu file sources (or database sources) may be in a bad state. We want to get these ones right as they cannot be enforced by the database itself (via FKs or constraints).
There is now a CreateContext method for retrieving a stand-alone context for threaded use.
We may want to add safety against this context being disposed (or just return a fresh one if it is).