Update libopenmetaverse to commit 6212cbd (Wed Jul 25 20:11:47 2012)

Built from https://github.com/openmetaversefoundation/libopenmetaverse/commits/master
This update incorporates a fix by Melanie in libomv where textures would sometimes rotate slightly when other properties were changed.
Hence addresses http://opensimulator.org/mantis/view.php?id=6100
This update also incorporates libomv bot code updates that significantly reduce the warning spam for pCampbot.
The change rate of libomv is low and many changes refer to bot or code not used by OpenSimulator, so I think it is sufficiently stable to use evne though it's not a release.
Remove a couple of compiler warnings pointed out by SignpostMarv
Replace libopenmetaverse commit 6212cbd with the same libraries but this time built with xbuild rather than nant.

This may fix Windows and some mono version builds.
Remove duplicated IScenePresence.PresenceType.  This is already in ISceneAgent.PresenceType from which IScenePresence inherits.

No other code changes required.
minor: Comment out unused MemoryWatchdog.m_churnRatePerMillisecond - this is currently calculated dynamically
Update OpenMetaverse libraries at commit 6212cbd, this time built on Windows
This is to try and resolve a strange Initialization exception for the AppearanceManager type that only occurs on Windows 64 bit (not Windows 32 bit or Linux!)
Remove the LandGeom checks in OdeScene - these are pointless since LandGeom is always IntPtr.Zero and contacts returned always have a valid geometry.

Possibly this was for a feature that was never implemented or was otherwise removed.
Thanks to SignpostMarv for the spot of the warning that shows this parameter was never changed.
adding asset cache and map tile directories to .gitignore
making first run more resilient to bad input (loop until good input, rather than crash)
Avoid a race condition between the scene shutdown thread and the update thread since commit c150320 (Thu Jul 26 15:27:18 2012)

c150320 started explicitly disposing of the physics scene and nulling it out on region shutdown.
However, the update loop may not have yet checked Scene.ShuttingDown, particularly if avatars were not in the scene, causing failure when it tried to lookup time dilation.
This commit moves the setting of m_shuttingDown above the existing 500ms pause to notify avatars that they are being kicked.
This should not affect the few other places that use this flag.
LSL/OSSL lacks Math.Min & Math.Max implementations.
Return world rotation on llGetObjectDetails()'s OBJECT_ROT
If we're fetching active gestures via the XInventoryServiceConnector, then properly look at the ITEMS dictionary already returned rather than the level above this.
Merge branch 'master' of ssh://opensimulator.org/var/git/opensim
BulletSim: add parameters and API calls for setting ERP and CFM.
Set ERP and CFM in linkset constraints.
Reorder rebuilding of object bodies so they are not rebuilt everytime
   something is linked and unlinked.
BulletSim: update the DLLs and SOs. This fixes the exception on shutdown
Adds support to ScriptModuleComms for region modules to export
constants to the script engine.
Fix bug in SoundModule.TriggerSound() where every sound update to an avatar would base its gain calculation on the previous avatar's gain, instead of the original input gain.

This was making sound attenuate oddly when there were NPCs in the region, though it could also happen with ordinary avatars.
Resolve a deadlock between INPCModule and SensorRepeat by replacing the SensorRepeat list with a new list on add/removes rather than locking it for the duration of the sensor sweep.

A deadlock was observed today where NPC removal on a script thread would lock the NPC list and then try to lock the sensor list via scripted attachment removal.
Concurrently, the sensor sweep thread would lock the sensor list and then try to lock the NPC list to check NPC status.
This commit resolves the deadlock by replacing the sensor list on update rather than locking it for the duration of the sweep.
Change exception log messages in XInventoryService connector to error rather than debug, since these signal real problems.

Also outputs full exception instead of just the message to aid diagnostics.