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.
Turning off the Detect Trap spell doesn't turn off the Night Vision spell any more.
The color of the fire protection aura has been changed from yellow to orange to make it different from the armor aura color.
You can now set the duration of fire protection in scripts.
Replaced or added sound effects of 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.