runescape-client: Added Animation runelite api file. Also renamed "skin" to "skeleton". (#2867)

* rename getSkin rsapi to getSkeleton

* Added animation runelite api. Also re-named method "getSkin" to "getSkeleton", because it is a more suitable description.

* re-named "skin" variable to "skeleton"

* added frames.java to runelite api

* added DualNode.java to runelite api

* made RSSkeleton extend Skeleton

* .

* removed unused imports

* checkstyle corrections

* put copyright notice back which i accidentally deleted.

* Added some descriptions

* removed type in description

* .

* added licence headers

runescape-api/src/main/java/net/runelite/rs/api/RSAnimation.java

@@ -24,12 +24,14 @@
  */
 package net.runelite.rs.api;
 
+import net.runelite.api.Animation;
+import net.runelite.api.Frames;
 import net.runelite.mapping.Import;
 
-public interface RSAnimation
+public interface RSAnimation extends Frames, Animation
 {
 	@Import("skeleton")
-	RSSkeleton getSkin();
+	RSSkeleton getSkeleton();
 
 	@Import("transformCount")
 	int getTransformCount();

runescape-api/src/main/java/net/runelite/rs/api/RSDualNode.java

@@ -24,9 +24,10 @@
  */
 package net.runelite.rs.api;
 
+import net.runelite.api.DualNode;
 import net.runelite.mapping.Import;
 
-public interface RSDualNode extends RSNode
+public interface RSDualNode extends RSNode, DualNode
 {
 	@Import("removeDual")
 	void unlinkDual();

runescape-api/src/main/java/net/runelite/rs/api/RSFrames.java

@@ -24,9 +24,10 @@
  */
 package net.runelite.rs.api;
 
+import net.runelite.api.Frames;
 import net.runelite.mapping.Import;
 
-public interface RSFrames extends RSDualNode
+public interface RSFrames extends RSDualNode, Frames
 {
 	@Import("frames")
 	RSAnimation[] getFrames();

runescape-api/src/main/java/net/runelite/rs/api/RSSkeleton.java

@@ -24,9 +24,10 @@
  */
 package net.runelite.rs.api;
 
+import net.runelite.api.Skeleton;
 import net.runelite.mapping.Import;
 
-public interface RSSkeleton extends RSNode
+public interface RSSkeleton extends RSNode, Skeleton
 {
 	@Import("count")
 	int getCount();