MoveByEntity component. Just updates the entity's position according to the speed of a target
Parallax. A special case of MoveByEntity that updates an entity's position in opposed direction to current camera's speed
ChaseEntity component. Tries to keep the entity within max-min distance from target.
To do: take PathBoundary into account, if present.
Little refactoring in Velocity Component
Simple test
Comments addressed + 1 minor fix in MoveByEntityComponent
Merge pull request #670 from jtorrente/movebyentity

Components for tracking entities' position