Changes of spell sounds.

Added sound effects of some spells: Lower armor — added
SND_SPELL_LOWER_ARMOR_END, Levitate — added SND_SPELL_LEVITATE_LOOP and
SND_SPELL_LEVITATE_END, Slow down — added SND_SPELL_SLOW_DOWN_END.

Repositioned spell sounds:

"Night vision", "Speed", "Telekinesis", "Lightning projection" and "Slow
time" — the completion sound is bound to the caster's current position.
"Armor", "Protection from fire", "Protection from cold" and "Levitation"
— the starting sound is bound to the spell origin; the effect sound
follows the caster; the completion sound is bound to the caster's
current position.
"Lower armor", "Curse", "Paralyze", "Slow down" and "Confuse" — the
starting sound is bound to the spell target.
"Harm" — the effect sound follows the caster.
"Raise dead" and "Summon" — the sound is bound to the portal location,
and the sound played only when the portal opens; the creature spawn
sound (for zombies, demons, etc.) is bound to the spawn point; the
completion sound is bound to the current position of the creature before
it disappears.
"Fake summon" (by NPC) — the starting and completion sounds are bound to
the position of spell target.
"Incinerate" — the starting and effect sounds are bound to the spell
target.
Changes of aura controls.

Turns on the aura for the "Lower armor" spell if the spell is active but
the aura is disabled. If a protection spell and "Lower armor" are active
at the same time on the same target, the lower armor aura is hidden.
Previously, the lower armor aura did not appear when protection ended
before the end of "Lower armor"; this is now fixed.