It turns out that child agent management has had a bug for a while: there was an inconsistency in the scope between opening and closing child agents in neighboring regions. For opening (in EnableChildAgents), the region's DrawDistance was being used; for closing (in IsOUtsideView) , the viewer's (SP) DrawDistance was being used. This fixes this inconsistency, therefore eliminating bugs observed in TPs between, at least, neighboring varregions.
This fixes the bug related to rebooting neighboring varregions while avatars are logged in; the avies would not see the region anymore until they relogged. Same problem as before: inconsistent calculation of scope.
On logout, delay the removal of AgentCircuitData until the very end, because that data structure contains important information about the agent that may be needed by modules.
Still log (but this time with warning rather than an exception) if we regenerate a new child caps seed for a region where we already have one.

I think it's still useful to know this to show up any errors early, but it's reasonable to still carry on rather than throw an exception.
Follow on from Diva's commit 9643792
Include option to remove auto backup files older than given number of days. New property created to specify how many days to keep files for. Off by default, also made sure only oar files will be removed.
When uploading mesh objects with textures also create inventory items for uploaded textures.

This implements:
http://opensimulator.org/mantis/view.php?id=7250
minor: put standard 'category' in brackets at front of log messages from previous commit 3d70db4a