Reduce default rotation AgentUpdate output sensitivity to a setting that cuts down UDP traffic without obvious adverse effects on observed avatar rotations.

Experimentally, on the Linden Lab grid the avatar can rotate slightly before triggering AvatarUpdates, whereas this is practically impossible in OpenSimulator.
These updates allow other avatars to see rotations, though sensitivity is low since other avatars can only be seen in one of 8 body rotations.
This commit changes sensitivity from 0.01 to 0.1, which better matches LL and reduces UDP traffic which has a beneficial impact on network and CPU load.
This has no impact on rotations in the simulator itself so simulation fidelity is the same as before.
To change this setting back for test/other purposes, edit RootRotationUpdateTolerance in the [InterestManagement] section of OpenSim.ini
Change MaxPoolThreads default in code as well from 15 to 300