Renamed the commonly used Position POJO into AdvancedPosition, as it also hold pitch, yaw and roll

Made GuiDropdown only accept instances of GuiEntryListEntry to avoid unneccessary toString() methods returning the name
Added GuiEntryListValueEntry which holds a Value and a Name to be displayed
Continued work on GuiObjectManager

src/main/java/eu/crushedpixel/replaymod/holders/AdvancedPosition.java

@@ -0,0 +1,51 @@
+package eu.crushedpixel.replaymod.holders;
+
+import eu.crushedpixel.replaymod.interpolation.Interpolate;
+import lombok.Data;
+import lombok.EqualsAndHashCode;
+import lombok.NoArgsConstructor;
+import net.minecraft.client.Minecraft;
+import net.minecraft.entity.Entity;
+
+@Data
+@NoArgsConstructor
+@EqualsAndHashCode(callSuper=true)
+public class AdvancedPosition extends Position {
+
+    @Interpolate
+    public double pitch, yaw, roll;
+
+    private Integer spectatedEntityID;
+
+    public AdvancedPosition(double x, double y, double z, double pitch, double yaw, double roll, Integer spectatedEntityID) {
+        super(x, y, z);
+    }
+
+    public AdvancedPosition(int entityID, boolean spectate) {
+        this(Minecraft.getMinecraft().theWorld.getEntityByID(entityID), spectate);
+    }
+
+    public AdvancedPosition(Entity e, boolean spectate) {
+        this(e.posX, e.posY, e.posZ, e.rotationPitch, e.rotationYaw, spectate ? e.getEntityId() : null);
+    }
+
+    public AdvancedPosition(double x, double y, double z, float pitch, float yaw, Integer spectatedEntityID) {
+        this(x, y, z, pitch, yaw, 0, spectatedEntityID);
+    }
+
+    public AdvancedPosition(double x, double y, double z, float pitch, float yaw) {
+        this(x, y, z, pitch, yaw, 0, null);
+    }
+
+    public double distanceSquared(double x, double y, double z) {
+        double dx = this.x -  x;
+        double dy = this.y -  y;
+        double dz = this.z -  z;
+        return dx * dx + dy * dy + dz * dz;
+    }
+
+    @Override
+    public AdvancedPosition newInstance() {
+        return new AdvancedPosition();
+    }
+}