add RBN stats + other fixes

add RBN stats + other fixes

Add some more comprehensive RBN stats (per minute, 10 minutes, hour).
Make the RBN spot cache global and make the inrush preventor code
work only on the first connection to skimmer provider.
Fix the $_isdbg clearing so that non-conditional logging messages
come out with a (*) in watchdbg and not the previous isdbg() sort.