Some fixes of spells

The player's magic level was limited to 1 while the RAF "word of power"
was active; now the limitation has been lifted.
Detect Trap Spell has been restored.
The color of the fire protection aura has been changed from yellow to
orange to make it different from the armor color. And you can now set the
duration of fire protection in scripts.
Replaced or added sound effects of some spells: Lower armor — replaced
SND_SPELL_ARMOR_START with SND_SPELL_LOWER_ARMOR, Speed — replaced
SND_SPELL_INVISIBILITY_END with SND_SPELL_SPEED_END , Protection from
fire — added SND_SPELL_FIRE_PROTECTION_LOOP and
SND_SPELL_FIRE_PROTECTION_END, Trap (Rune of guarding) — replaced
SND_SPELL_FIRE_HIT with SND_SPELL_RUNE_OF_GUARDING_END, Ice field —
added SND_SPELL_ICE_FIELD_LOOP and SND_SPELL_ICE_FIELD_END, Incinerate
and Mass Incinerate — replaced SND_FIREPLACE with
SND_SPELL_INCINERATE_LOOP and added SND_SPELL_INCINERATE_END.