cache: ensure we warm stablerange cache before the obshashrange cache I've been seeing traceback that seems to be happening because of issues in this area.

evolve: fixing obscache invalidation This was missing a call to the parent's destroyed(), such that any transaction after stripping some nodes would result in a crash (by attempting to read nodes which were stripped).

obshashrange: warm the cache at the end of each transaction This will help having warmed cache for read only client. The warming is still imperfect in case of markers that trigger a reset, but we are in a better place than what we used to be.

obshashrange: warm cache outside of loops The performance impact will be lower

obshashrange: "update" the cache on each transaction close Right now the "update" does not really file the cache, but it will detect invalid situation and clean them.

obshashrange: properly invalidate the cache on destroyed Copy paste is the scurge of code source.