cocos2d-x 同时播放多个音效的时候，会发现有的音效放不出，有的循环音效放着放着就没了
后来发现猫腻在Cocos2dxSound.java里：
private static final int MAX_SIMULTANEOUS_STREAMS_DEFAULT = 5;
SoundPool构造的时候要指定并发音频流的数量
public SoundPool (int maxStreams, int streamType, int srcQuality)
Added in API level 1
This constructor was deprecated in API level 21.
use SoundPool.Builder instead to create and configure a SoundPool instance
Constructor. Constructs a SoundPool object with the following characteristics:
Parameters
| maxStreams | the maximum number of simultaneous streams for this SoundPool object |
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| streamType | the audio stream type as described in AudioManager For example, game applications will normally use STREAM_MUSIC. |
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| srcQuality | the sample-rate converter quality. Currently has no effect. Use 0 for the default. |
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Returns
这里cocos2d-x设置成5了（I9100设成3），可以手动改大一点，来解决问题
版本：cocos2d-x 3.0