fixed equip and loadGame crash

Fixed some things that crashed my game.
The item->getEquipmentSlot() throws an exception saying that canEquip() is false. After things had been made in the workshop and a creature tried to pick them up it would throw out the exception. The order the of the function calls seems to matter because of the short-circuit evaluation of &&.
When loading a save file I got a segmentation fault because in Creature::hasSkill(Skill* skill), skill->getId() returns some uninitialized value which is outside the bounds of skills. Re-initializing Skill seems to fix this.