BulletSim: remove unuseful BulletSim parameters from OpenSimDefaults.ini and
replace with things someone might actually want to tune (avatar height, ...).
Add region heartbeat start event to complement heartbeat end event.
This allows object modification before the usual heartbeat operation.
Add methods to Animation and AnimationSet for easier manipulation and
display of groups of animations (Equal(), ToString(), FromOSDArray(), ...).
No functional change to animations.
Trigger OnScenePresenceUpdated when the avatar's animations change.
Merge branch 'master' of ssh://opensimulator.org/var/git/opensim