Implement sound-playing API

There's no playSoundEffect-equivalent method in the actual client code.
Instead, the client just adds some values to the 4 sfx arrays, removes
any old queued sound effects, and then bumps the counter, which is what
I've done as well.

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

@@ -352,6 +352,27 @@ public interface RSClient extends RSGameEngine, Client
 	@Override
 	boolean isIgnored(String name);
 
+	@Import("audioEffects")
+	RSSoundEffect[] getAudioEffects();
+
+	@Import("queuedSoundEffectIDs")
+	int[] getQueuedSoundEffectIDs();
+
+	@Import("soundLocations")
+	int[] getSoundLocations();
+
+	@Import("unknownSoundValues1")
+	int[] getUnknownSoundValues1();
+
+	@Import("unknownSoundValues2")
+	int[] getUnknownSoundValues2();
+
+	@Import("queuedSoundEffectCount")
+	int getQueuedSoundEffectCount();
+
+	@Import("queuedSoundEffectCount")
+	void setQueuedSoundEffectCount(int queuedSoundEffectCount);
+
 	@Import("rasterProvider")
 	@Override
 	BufferProvider getBufferProvider();

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

@@ -0,0 +1,29 @@
+/*
+ * Copyright (c) 2018, SomeoneWithAnInternetConnection
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.runelite.rs.api;
+
+public interface RSSoundEffect
+{
+}