stablerange: also respect the 'warm-cache' config This will help large install to enable obshashrange as "opt-in" without impacting other repositories.

debugstablerange: cleanly "Abort" when no revision are specified Previously we had a traceback from a max on an empty sequence.

stablerange: use last recently used caching for revisions associated to ranges This does not make things faster but at least it make them able to finish on large repositories.