MAINT-6380, SL-399 - vertical flicker related to joint offsets for mPelvis. Having a joint offset for mPelvis is still a bad idea, but it won't cause as much flickering now.

SL-276 - small skeleton file tweaks to 'end' and 'connected' attributes (no functional impact on viewer)

MAINT-6484 - make the attachment pos updates a bit smarter, so we don't flag the pelvis has having changed unless it has actually changed. Avoid excess calls to computeBodySize(), which can cause a vertical position glitch.

SL-315 - arche_tool.py updates, resetSkeleton() now preserves mPelvis state, forces all params to be updated.

SL-315 - resetSkeleton(), working for bones at least partially, still some issues with collision volumes

MAINT-6392: Do not change the URL used for getting cookies (except to pass it to CEF) The original URL is used for HTTP Core access to profile functionality.