Add isPaused() and isStopped() methods to Sound interface

api/src/main/java/com/bartlomiejpluta/base/api/audio/Sound.java

@@ -9,6 +9,10 @@ public interface Sound {
 
    boolean isPlaying();
 
+   boolean isPaused();
+
+   boolean isStopped();
+
    void setGain(float gain);
 
    void setRepeat(boolean repeat);

engine/src/main/java/com/bartlomiejpluta/base/engine/core/al/source/AudioSource.java

@@ -59,6 +59,16 @@ public class AudioSource implements Sound, Disposable {
       return alGetSourcei(id, AL_SOURCE_STATE) == AL_PLAYING;
    }
 
+   @Override
+   public boolean isPaused() {
+      return alGetSourcei(id, AL_SOURCE_STATE) == AL_PAUSED;
+   }
+
+   @Override
+   public boolean isStopped() {
+      return alGetSourcei(id, AL_SOURCE_STATE) == AL_STOPPED;
+   }
+
    @Override
    public void setRepeat(boolean repeat) {
       alSourcei(id, AL_LOOPING, repeat ? AL_TRUE : AL_FALSE);