Implemented ArmorStands & Prepared for Vector upgrades.
-Added support for ArmorStands in (set_)entity_spec and get|set_mob-equipment.
-Added docs section for ArmorStand spec, and fixed missing Arrow specs probably.
-Renamed c.l.a.Velocity to better reflect how we are using it.
-setup some Velocity features to be implemented in a future commit.
Merge pull request #239 from jb-aero/master

Implemented ArmorStands & Prepared for Vector upgrades.

Thanks jb-aero!