Add in IQ bonus for PI per B77

[tsykoduk]

Adding in clerical spells to a test character:

Int 10 Power Investiture 2

Added Minor Healing (IQ/H) from the cleric spell list in DF at 1 point, ended up with a skill of 8.

Moved Power Investiture to 1, still had a skill of 8.

With this change

Int 10 Power Investiture 2

Added Minor Healing (IQ/H) from the cleric spell list in DF at 1 point, ended up with a skill of 10.

Moved Power Investiture to 1, with a skill of 9.

Seems to follow the rule on B77: "Add your Power Investiture to your IQ when you learn spells granted by the deity who bestowed this advantage."