Add movement/acceleration/velocity components + movement system

core/src/com/me/asteroids/components/AccelerationComponent.java

@@ -0,0 +1,10 @@
+package com.me.asteroids.components;
+
+import com.badlogic.gdx.math.Vector2;
+import com.me.common.ecs.Component;
+
+public class AccelerationComponent extends Component {
+
+    public Vector2 acceleration;
+
+}

core/src/com/me/asteroids/components/PositionComponent.java

@@ -0,0 +1,11 @@
+package com.me.asteroids.components;
+
+import com.badlogic.gdx.math.Vector2;
+import com.me.common.ecs.Component;
+
+public class PositionComponent extends Component {
+
+    public Vector2 position;
+    public float rotation;
+
+}

core/src/com/me/asteroids/components/VelocityComponent.java

@@ -0,0 +1,11 @@
+package com.me.asteroids.components;
+
+import com.badlogic.gdx.math.Vector2;
+import com.me.common.ecs.Component;
+
+public class VelocityComponent extends Component {
+
+    public Vector2 velocity;
+    public float maxVelocity;
+
+}

core/src/com/me/asteroids/systems/MovementSystem.java

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+package com.me.asteroids.systems;
+
+import com.badlogic.gdx.math.Vector2;
+import com.me.asteroids.components.AccelerationComponent;
+import com.me.asteroids.components.PositionComponent;
+import com.me.asteroids.components.VelocityComponent;
+import com.me.common.ecs.Entity;
+import com.me.common.ecs.EntitySystem;
+
+public class MovementSystem extends EntitySystem {
+
+    private Vector2 tmp = new Vector2();
+
+    public MovementSystem() {
+        super(PositionComponent.class, VelocityComponent.class);
+    }
+
+    @Override
+    public void processEntity(Entity entity, float dt) {
+        PositionComponent positionComponent = entity.getComponent(PositionComponent.class);
+        VelocityComponent velocityComponent = entity.getComponent(VelocityComponent.class);
+
+        Vector2 velocity = velocityComponent.velocity;
+        float maxVelocity = velocityComponent.maxVelocity;
+        Vector2 position = positionComponent.position;
+
+        AccelerationComponent accelComponent = entity.getComponent(AccelerationComponent.class);
+        if (accelComponent != null && !accelComponent.acceleration.isZero()) {
+            velocity.add(tmp.set(accelComponent.acceleration).scl(dt));
+        }
+
+        if (!velocity.isZero()) {
+            velocity.clamp(0, maxVelocity);
+            position.add(tmp.set(velocity).scl(dt));
+        }
+    }
+
+}