following promotion of DRTVWR-497

following promotion of DRTVWR-503

Character lights injected during render pass while in character edit mode
(i.e. mSpecialRenderMode == 3) were causing discrepencies between deferred
(ALM) and forward alpha blend lighting.

Removed some potential div-by-0 NaNs and a mangled clamp.

Revert "SL-13768 Remove glow from moon when sun is down due to it using the sun glow setting (pull request #297)"

SL-13830 Remade vivox shutdown to terminate when it is told to shutdown instead of when viewer is quiting

Got into D503 by accident

LN (EKU_TLS) is more likely to be present thus should be checked first

This reverts commit 92499ce1.

# Conflicts:
#	indra/newview/llinventorybridge.cpp
#	indra/newview/llinventorypanel.cpp
#	indra/newview/llinventorypanel.h

This reverts commit 25fd4c2b.

Had to find a balance in the sunlight intensity calculation that behaves correctly for
both these issues.

LLWorld is supposed to first remove region from list, then delete the region, but in case of this crash region was returned by handle from llworld yet was mDead and cleaned up, all in main thread.