Added a constraint to ensure that the avatar's height (with offset)
does not go below 0.1 meters. Camera was getting confused since the avatar's
effective height was negative.
Note the avatar is mostly underground/contorted even at 0.1 meters, but
most users setting values this low will be making ultra-tinies and would
be hiding the avatar mesh. Camera stays above ground when height is at 0.1.
Conflicts:
indra/llappearance/llavatarappearance.cpp
