New class : The pet master! Objective system! Game completion Tree!

For any questions, our discord! http://discord.gg/planetcentauri

***New class! The pet master will allow you to control up to 4 pets simultaneously! (Standard one + pet slot + mount + bonus pet) ***

Objective system & Game completion Tree will (especially new player) guide you in the evolution of your progression and mechanics

Changelog 0.13.13

Adds:
- Objectives system, game completion tree (F4)
- New class, the pet master (steel armor) with 4 skills:
 - Mount Invokation: Summon the monster assigned to the slot 5 as a mount. It's level scale with the sum of MP/HP/SP max
 - Pet Invokation: Summon the monster assigned to the slot 6. It's level scale with the sum of MP/HP/SP max.
 - Heal Pets: Heals all invoked monsters.
 - Resurrect Pets: Resurrects all monsters in the toolbar.

Fix:
- Spell can't be maintained when in the sword slot
- Misc...