Expand scarecrow behavior to three options

[GSKirox]

Change the free_scarecrow option to scarecrow_behavior with 3 options :

• Vanilla
• Fast : you don't need to play the song to summon Pierre, just to pull an Ocarina, but you still need to set a song to child and adult Bonooru. This is logically identical to Vanilla.
• Free : same behavior as the old free_scarecow option.

[r0bd0g]

I guess don't forget to make this work together with #2221 when that comes in.

[fenhl]

I forgot, why was this tagged as waiting for author?

[GSKirox]

Because i needed to make it work with #2221 which was merged before this one. Which is done in the most recent commit.